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Kerry Sieh in Sumatra - January 2005

For a map of Sumatra, please click here.
For a map of the Sumatran subduction zone, click here.
Click here to view photos of Kerry Sieh's journey to Sumatra.
An essay by Sieh that appeared in the January 10 edition of Time Asia.

For a decade, Caltech's Kerry Sieh has been researching the suspect terrain of the Sumatran plate boundary, where the 9.0 Aceh earthquake occurred on December 26. Last summer he and his colleagues distributed brochures to people living on local islands to explain the area's geology, and suggest ways to limit future damage. On January 1, Sieh traveled to Indonesia, and over the following three weeks, shared, via e-mail, his personal observations and preliminary science findings.

Dear Colleagues and Friends,

I arrived in Jakarta late in the morning yesterday (January 1, 2005), nearly a day after departing Los Angeles. Just walking around this bustling capital city of Indonesia, one would not know that a major disaster had struck the northwestern corner of the country just a week ago. In the evening I met with Danny Natawidjaja and Bambang Suwargadi, my colleagues from the Indonesian Institute of Science (LIPI), to compare notes on our preparations for field work in western and northern Sumatra.

We knew several days ago from friends in Padang, the large coastal city of West Sumatra, that it had escaped damage from the tsunami. Now there is additional good news from two sites on the Mentawai and Batu islands, off the west coast of Sumatra, where we have GPS stations and many local friends. In Sikakap, the main town of South and North Pagai islands, they report that the tsunami was only about a meter (three feet) high and did not injure anyone, but flooded stores and homes. A similar story comes from Tello, the main town of the Batu islands: Relatives of friends of Danny report that the tsunami washed into the main street but caused no injuries. Both of these towns are on the east coast of their islands. We still have no word from friends in the villages on the more exposed western coasts of the islands, but fear that the tsunami height will have been greater there.

In Padang, there are reports that many people fear that a large tsunami will soon devastate the city from a large aftershock. Large tsunamis did strike the city following the giant earthquakes of 1797 and 1833, so their fears are not baseless. But we have no reason to believe that such an event is imminent. We expect to have discussions with local officials about these concerns when we arrive around January 6. Even if there is no imminent threat to Padang, we know that it will be in a precarious position when the Mentawai section of the megathrust, just offshore, next ruptures. I wonder what urban planners and civic authorities should do in a situation like this?

We are hoping that a subset of our group will begin to download information from the Sumatran GPS Array (SuGAr) stations on the 6th, starting with Jambi in eastern Sumatra, then going on to the three stations on the mainland south of Padang, to measure the crustal movements during and after the earthquake. Simultaneously, another subset of the group would conduct a reconnaissance by fixed-wing aircraft of Simeuleu island, southwest off Aceh's coast and very close to the earthquake's epicenter, and of other, neighboring small islands. There we expect to see evidence of uplift, if these islands were above the rupture. We also hope to reconnoiter the west coast of Aceh, at the northern tip of Sumatra, to survey evidence for submergence due to the earthquake, east of the megathrust rupture. We would like to get a few measurements of vertical deformation in both areas, to help guide a mission to document more thoroughly the deformation pattern. But we are not sure if the dire humanitarian situation on the coast of Aceh will allow us to make measurements on the ground. One media outlet reported yesterday that Simeuleu island has survived the quake and tsunami relatively well. Islanders there have a tradition of running for high ground when they feel a big earthquake, based upon their ancestors' experience in the 19th century. On about the 9th, we hope to begin downloading SuGAr stations on the Mentawai and Batu islands by helicopter.

Today, we hope to meet with representatives of Bakosurtanal, Indonesia's national surveying agency, to synchronize plans to resurvey geodetic monuments in the source region. We also expect to meet with aviation companies to discuss arrangements for our fixed-wing and helicopter flights.

Tuesday evening, January 4. Jakarta

So far, everything is coming up roses with respect to getting our official travel permits from the scientific organization LIPI, the political offices (Sospol), and the national police (PolRI).

Yesterday we had a press conference at the headquarters of Pasifik Satelit Nusantara, a private company that is partnering with us to develop telemetry (satellite-based telecommunication). About 60 print and television journalists attended to listen to Danny and me explain the science of the megathrust that produced the December 26 earthquake. Many stations broadcast the conference. One station caused a panic in Padang by editing Danny's comments in such as way as to make it sound as if we thought a giant tsunami was imminent there. Danny was scheduled to go on national TV tonight, live and uneditable, to attempt to quell concerns. We are going to be in Padang and on the nearby islands in less than a week, so obviously we think the likelihood of another giant earthquake and tsunami is very small.

Yesterday we also met with a prominent former minister and a former ambassador to discuss the trouble in Padang and to discuss the longer-term problem of how to mitigate the effects of the eventual earthquake and tsunami there. We also met with the head of LIPI to discuss our desire to reconnoiter the stricken area by helicopter rather than by boat and on foot. Today, the heads of the office, Pak Jan and Pak Umar, told us that they have arranged with the military to move us around in a helicopter for the time that we are in Aceh. We need to firm this up and discuss the particulars tomorrow.

For our downloading of SuGAr stations south of the equator, we contracted today with a private helicopter company to take us to the island stations between January 9 and 12. It will be strange to see from a fast helicopter the islands that we have visited so many times by slow boat. Today, while calculating our itinerary, I could not get used to the fact that distances that usually take us 12 hours to traverse by sea will only take us an hour or so by air.

We learned that two teams of surveyors from Bakosurtanal were flying today to Nias island, west of Sumatra, to begin their resurvey of the campaign GPS monuments of Yehuda Bock and his colleagues, scientists with the Scripps Institution of Oceanography. I'm sure they will recover spectacular evidence of deformation from the region of the earthquake.

We have pretty much decided to install the four new continuous GPS stations on Nias and Simeuleu islands, and on the mainland Aceh coast, to monitor post-seismic transients. (Because the earth's crust is elastic, it will rise or fall during an earthquake. Then, over a period of years it will rebound, or return to some degree, with respect to its original position.) Originally, these new stations were to go in south of the Equator, to densify the existing network.

The meeting with the vice president of Indonesia today (Tuesday) lasted over an hour. We explained the potential scientific value of the continuous GPS network for monitoring the "heartbeat" of the Sumatran megathrust and suggested an international meeting within a month or two to bring together scientists from around the world who were working on various aspects of the earthquake and its effects. The vice president asked about the value of an early detection and warning system for tsunamis. We suggested that it would be in the best interests of the Indonesian people to make sure that such a system for the Bay of Bengal be able to issue a warning within a minute or so, since the tsunami could arrive on the shores of western Sumatra and its islands within just minutes of the occurrence of the earthquake.

On a personal note, what a joy it was yesterday evening to treat myself to a short jog on the treadmill and a little bit of exercise after a day driving around Jakarta in taxi cabs and being in meetings! No such luck tonight - the meetings weren't over until after 10 p.m.

It appears that we will arrive in Padang on January 7 and fly out to the islands on the 8th.

Thursday morning, January 6. Jakarta

Dear Colleagues and Friends,

Yesterday afternoon, the hotel was flooded with delegates to the international conference on relief for the earthquake and tsunami victims. All are walking around with big placards on their chests, color-coded to indicate the country they represent. Earlier in the week I was nearly alone on the fifth floor of the hotel. Now I share it with the Myanmar delegation and two Indonesian security officers, who are in the hallway all day and night to protect them. They look pretty bored, so I talk to them in my very broken Indonesian as I'm coming and going, to make their day a little more interesting.

Logistics are in their final stages. Rifki, from PSN, the satellite communications company, just brought us two more satellite phones so the various subgroups of the team can keep in contact with each other during the helicopter downloads on the islands. Our Caltech colleague John Galetzka, who is almost always in the field taking care of equipment and field logistics for us, is stuck in Singapore trying to get his visa in less than the typical two-day turnaround. The chairman of LIPI, the Indonesian Institute of Science, sent a special letter to the embassy yesterday afternoon, pleading that the visa granting be expedited, since John's participation in our work in the stricken region is essential to our success. Looks like it's not going to happen, anyway. I just met with Cecep, the Indonesian geodesist from Bakosurtanal (Indonesia's national surveying agency) and with Scripps's Yehuda Bock's principal collaborator, to coordinate our GPS work. We'll do the continuous measurements; he'll focus on reoccupation of the old monuments that Yehuda's group surveyed back in the 1990s. They will see huge changes across northern Sumatra, I'm sure; we'll see small changes, since the Sumatran GPS Array (SuGAr) network is more than 300 kilometers (185 miles) south of the rupture area.

Yesterday a few geologists forwarded me an article by a reporter who had interviewed me before I left Caltech. I was amazed to learn that someone could do such a thorough job of misrepresenting what I had said, even to the point of inventing quotations. I guess the hunger to dramatize and sensationalize is as strong as the desire to eat.

When I woke this morning, I found in my e-mail inbox a message from one of my friends in Padang, a city of nearly a million people on the western coast of Sumatra. It is in a setting not unlike that of Meulaboh, the western Aceh city that was devastated by the tsunami. It is directly landward of the giant earthquakes that we have been studying using coral reefs and GPS, and has a history of giant tsunamis. The most recent big ones were in 1833 and 1797.

Madi, my friend, is a young guy who works in the hotel where our group often stays. He earns about a dollar a day making up rooms and doing other tasks there.

Here is his e-mail to me:

"kerry apa kabar, you know i' am afraid if the happent come here, i'm not care about myself, but my parents and sister, you know the tsunamis issue will come here many people say like that now, so my father got accident last week, his left feet was broken, it's very hard to me, I hope you can give me about the information, what will happent here after that, I know you are very busy with this situation, so I saw you in metro tv yesterday with mr. Denny, thanks kerry, see you madi"

For the past four days, there has been much panic among the residents of Padang because they fear that a tsunami may be imminent. We are hearing reports that some people, like Madi's father, have actually been injured. One reason for the panic is that people don't realize that any such tsunami would be presaged by a very large earthquake.

Our posters and brochures and our lectures in churches and schools have thus far been restricted to the islands offshore of Padang, where the towns are small and it is easier to educate people. We had been in discussions with the authorities in Padang last July and August about how best to educate this much larger population. The situation is particularly difficult because there is no way, even with a 15-minute warning from the earthquake itself, that most of the city's inhabitants could escape landward.

On the scientific front, I was excited to get a report from Joann Stock, my colleague and fellow geology professor at Caltech who's been on sabbatical in Japan. She sent a report filed by Roger Bilham (a geophysicist at the University of Colorado), stating that in India's Andaman islands, located in the southeastern part of the Bay of Bengal, the west coast of the islands appears to have risen and the east coast submerged during the earthquake. This would mean that the rupture did, indeed, propagate as far north as the Andamans. This must be considered good news for the residents along the coasts of the Bay of Bengal, because it means that most of the subduction zone between Myanmar and northern Sumatra ruptured during the earthquake (Myanmar is roughly 634 kilometers--390 miles--from northern Sumatra). Thus, the likelihood of another giant tsunami is probably not very high. Caltech seismologist Chen Ji also forwarded a report stating that an island in the Nicobar chain, located near to the Andamans, rose 3 meters, almost ten feet, exposing the coral. Both of these reports describe landward tilting of the outer-arc islands, just like we see in the ancient corals off West and North Sumatra during large earthquakes there in 1797, 1833, and 1935.

I was delighted and relieved to have an e-mail from our Mentawai (islands) friend, Juniator Tulius, yesterday evening, saying that he and his wife had just arrived in Padang from the islands safe and sound. He reports that a small tsunami occurred at the town of Saibi after the earthquake, but that it didn't even flood the houses. He also said that he and the villagers didn't even feel the earthquake. He also reports no damage or loss of life in the towns of Tuapejit or Sioban, on the east side of Sipora island, another in the Mentawai chain. But he has heard no word from villages on the west coast of the islands. Caltech's John Galetzka said today that he felt the earthquake hundreds of miles away to the north, near the Burmese/Thai border. And an American friend of mine, who runs a hotel on the harbor in Padang, said over the phone to a reporter that she saw the tide flow out rapidly after the earthquake. I'm sure we'll have many more stories to tell once we get to the islands.

Friday night, January 7, Padang Hotel, Padang, Indonesia

I have finally left Jakarta for the west coast of Sumatra. The rest of the crew follows on Saturday morning. The first good news of the day was that Caltech's John Galetzka, who takes care of our equipment, got his visa in Singapore and will be arriving in Jakarta in the early afternoon. Bambang, our main logistics guy, was nervous about being able to get the two requisite permits from government offices late on a Friday afternoon.

Stepping off our 737 at the airport in Padang, I saw a familiar scene--a dozen porters in green overalls ready to pounce as we entered the terminal and began the raucous process of claiming our baggage. After I found my bags, I waded through the crowd and found our long-time assistant, Imam, and his wife, Susi, waiting for me. We loaded my baggage into the "Imam-mobile," his old clunker that miraculously still functions, and we were on our way to the little white Padang hotel. We are staying in the one-story part of the hotel, about a kilometer from the beach. Our old favorite, the Tiga-Tiga Hotel, burned about a year ago. It was only about 500 meters (500 yards) from the beach, across the street from the main bus terminal. The bus terminal was moved to a more remote location on the edge of the city about two years ago, and now I see that an enormous new marketplace is being built in its place. It is four stories tall and made of the standard materials--concrete pillars and beams, with an abundance of fill-in brick. I see a shear wall running perpendicular to the beach, but I have no idea how the building will fare in a giant earthquake.

Our first snag this afternoon came when we attempted to change U.S. dollars to rupiah (Indonesian currency), for buying the food that we will need for the next couple of weeks on the islands. The current rate for rupiah is 9,200 per U.S. dollar. The clerk leafed through the $3,500 of brand new $50 bills and inspected them carefully. I stood there smugly, knowing they were pristine and without any marks, folds, or minor tears that would lower the exchange rate. She looked at me and casually announced that she would have to lower the rate by 3 percent because the serial numbers all began with "CB." I refused to cash them, even though I knew it was too late to go to a bank. I asked what other serial numbers were suspect of being counterfeit, and she said only ones beginning with "CB." So back we went to the hotel and retrieved a similar amount of $100 bills, for which we got the 9,200 rate.

I went to visit my friends at the Batu Arau Hotel, a beautiful structure that used to be a Dutch bank. It sits about a kilometer in from the sea on the north bank of the filthy river that serves as a harbor for fishing boats and surf charters. Christina and Chris Fowler run a surf charter and hotel/restaurant from there. There were a couple of people from Bali at the hotel, organizing relief efforts. Christina was overjoyed to see me and threw her arms around me, exclaiming something like, "You warned us, you told us, and it was just like you said!"

I broke my self-imposed silence with the media (too many requests for interviews and just not enough time) and e-mailed a reply to a reporter in Banda Aceh. The reason is that our attempts to find air support to survey the region along the west coast of Aceh, both north and south of Meulaboh, have not borne fruit. So I am interested in the possibility that we might hook up with a media person who has access.

We are fine now as far as getting to Simeuleu Island, off the west coast of Sumatra, with our helicopter and boat support. But this still doesn't help us get an aerial recon of the west coast. So, after about January 13 or 14, our transportation is still up in the air.

I'm anxious to get to the islands to start our research. From now on, though, communication will be limited to satellite phone.

6 a.m., Sunday, January 9. Padang Hotel, Padang, Sumatra

Restless night here, anticipating our departure for the islands off the west coast of Sumatra. Caltech's John Galetzka, our equipment/logistics guy, left the room at 2 a.m., to begin the six-hour drive south to the Sumatran town of Muko-Muko. Joining him are Felix (the technician/engineer from ACeS, the satellite telecom company we are working with), and Bambang, our other logistics person. They will download the two GPS stations down there, and at about 11 will fly in two helicopters. Bambang will go to the Silabu GPS station on the west coast of North Pagai Island, and John and Felix to the Perak Batu station on the east coast of South Pagai Island. We have two helicopters because an Australian TV crew rented one to follow us around for a couple days. Now they don't need the helicopter until the afternoon, because they are coming over with us in the speedboat loaned to us by the local Bupati (the equivalent to a county supervisor).

The helicopter fuel for operating on the islands had not yet arrived by midnight last night, so Imam, our boat captain, and the crew of our big boat will wait until it arrives before leaving the harbor for the 14-hour trip to Sikakap (a town of about 1,500 people on North Pagai Island). The big boat will be accompanying us up the island chain, carrying the fuel for the helicopter and providing our food, fresh water, and beds.

My colleague Danny Natawidjaja and I leave at 7 a.m. for Teluk Bungkus, the big harbor an hour to the south of Padang, where we'll board the Bupati's speedboat with the TV crew. We expect to arrive at Silabu by about 11:30 a.m., about the time that Bambang will arrive by helicopter.

Last night I took one of our educational posters (about earthquakes and possible tsunamis) over to the Batang Arau hotel at the harbor, which is run by my friends Christina and Chris Fowler. Christina had told me she'd really like to have another one, now that the tsunami has happened.

She had just spoken with Chris via satellite phone. He is distributing relief supplies to the villages of the west side of Nias Island, which were hit very hard by the waves. He reports several hundred deaths and, in some villages, a nearly complete loss of their fishing fleet and, hence, livelihood. At his recommendation, Imam and our helper Susi are buying a range of antibiotics (you can get them over the counter here) and fishing materials (nets, fish hooks, and line). Yesterday Susi was intent on buying dozens of pairs of ladies' underwear to distribute. She was very concerned that they would be in short supply of this item. When I asked why not mens' as well, she said men don't need them as much! So anyway, I guess we'll be distributing ladies' underwear as part of our little relief effort. (The things I do in the course of trying to do science!!)

At about 5:30 this morning the screeching from the minarets began here in town, calling the faithful to prayer. It is an indication that everything here in this very vulnerable city has gone back to the normal cycle of a normal day. The images of the disaster in Aceh continue to flood the local and national television channels, but people have by and large resumed their lives, as if nothing had happened. Yesterday, in the business center of the Bumi Minang Hotel, where I went to send my last e-mails, the girl who runs the office recognized me from a national television interview a few days ago. She asked me if I was staying at the hotel. When I said no, she asked why. I just bit my lower lip gently, to keep from saying something that might frighten her. She saw my hesitation and sensed that I was not comfortable answering. She managed to drag out of me that I felt the hotel was too close to the water and too big of a structure for me to feel safe spending a lot of time there (in the event of a large aftershock and a possible tsunami). Her playful mood became more somber. Later I learned from Danny that she had asked him the same questions and his answers had been the same as mine. I wonder how in the coming years we are going to approach the massive educational program that will be necessary to help the citizens of the large cities and villages along the coast to figure out how to cope with their problem.

1:30 p.m., Sikakap, principal town of the Pagai Islands

It only took about five hours to cross the Mentawai straits to Sikakap on North Pagai Island (the Bupati's boat cruises at an amazing 20 knots, whereas our usual boat only goes about 10 knots or so). Many of our old friends greeted us as we walked through the town to reserve rooms in Pak Edi's hotel (the Wisma Lestari) and find a restaurant for a quick lunch.

I was surprised to see no evidence of the tsunami here. A young guy with yellow plaster on his face, sitting on a tugboat, hailed me. Oops, I've forgotten his name; maybe it's Frizal, the guy in charge of the fishermen's' harbor. I think he said he was on the tugboat at the time and that the water poured over the wharf and into the grassy field between the wharf and the street. That suggests a surge about a meter (three feet) above high tide. Our two most reliable friends told us what happened. Pak Edi says that the tsunami started with a withdrawal of the sea and rose up to the middle of the highest step of his house. I judge that to be about two meters above mean tide, but I'll have to pin this down a little better tonight. (My later measurements show that the maximum height was about 70 centimeters, a little more than two feet, above the sea level before the tsunami.) The biggest surge came at about 3 p.m. here. My friends Devi and her husband, Abeng, told me that the surge nearly filled the gully beside her house, but did not go into the street. I walked to the waterfront there and estimate that this would have been about a meter above the current water level. Pak Edi says the surge came during high tide. So, at first glance, it appears to me that the surge was only a meter or so, much less than in Padang.

Off to Silabu now, on the west coast of North Pagai Island, cruising through rough, choppy swells.

We arrived late by speedboat at the mouth of the small mangrove-lined river that leads to Silabu. It only took us about an hour and a half to find a longboat to get us the two kilometers (mile-plus) up the river, say hello to our friends, and meet Bambang and the helicopter. We arrived at the village at about 4:15 p.m. with the unusually high tide still rising over the grassy embankment. Every time I emerge from the mangroves to the little wooden homes, pigsties, and wharves of Silabu, I feel like I've entered the riverbank of The Wind in the Willows! So quaint and peaceful. Patroni and Suardi greeted us, two of the friends we made last August when we installed the GPS instrument, along with a coterie of small kids and mothers.

We learned that the tsunami arrived at about 3 p.m. as a draining of the river. The river is probably about two meters deep and was drained completely dry. Five minutes later or so, it filled again but did not top the banks. Ebbing and filling happened many times in the course of the day. The return of the water up the river brought an abundance of dead fish. I'm guessing that the draining of the fresh water into the bay killed the salt-water fish, which were then swept back in with the refilling of the river.

Everyone was all smiles as we walked along the concrete sidewalk through the town. Bambang had arrived an hour before in the helicopter and was downloading data. Patroni walked with us up from the river to the GPS station, all the while telling us that all the villagers felt that our instrument had saved them from harm. We were thankful that they had such a good opinion of us and our instrument, but reminded them that the instrument was just that--an instrument, not a protection--and if they ever feel a big earthquake they must immediately run to the high ground in the church yard, where the instrument is. Nonetheless, Patroni re-affirmed that we and the instrument had been sent by God, just in time. Otherwise, how could both Bambang and we have arrived within an hour of each other--us by boat and him by helicopter?

We put the three guys in our group who were prone to seasickness on the helicopter for the return flight to Sikakap, while we went back to the boat for the return ride. Good decision--the chop made it a bit harrowing to get to the speedboat in the dugout, but here we are out in sea in a choppy two-meter swell, motoring back to town. Just dove into a huge one, in fact, that bent the railing on the bow. We're all a bit nervous.

1:20 p.m., Monday, January 10. Wisma Lestari (a small hotel at the waterfront in Sikakap)

We have been frustrated by the choppy seas all morning, unable to leave safely for Perak Batu, a village on the east coast of South Pagai Island, where we have an instrument. Since our big boat was unable to cross from Padang yesterday, because of the choppy seas, we have only enough helicopter fuel to make one trip back and forth from P.B. The TV crew needs to film us there, but we can't take them and us on the same trip. So an hour ago we decided to have their crew cross the strait in a boat, rent motorcycles, and drive as far as they can toward P.B. on the logging road that cuts southward along the ridge crest of the island. Three of us will fly down and be deposited at P.B., then the helicopter will pick up the motorcyclers nearby. Should be able to do everything before dark.

This noon, as I ate lunch at a small family restaurant, I watched on television the terrifying images of the tsunami surging through Banda Aceh, chock full of cars, and wood, and other debris. I looked around at the dozen or so men, women, and children around me and started to tear up. Are they going to be the next victims, when the great Mentawai earthquake happens? It's much easier to take if you don't know the victims. If you have gotten to know many of them, and then they are swept away in a tsunami or crushed in a collapsing building, how do you cope? The grief of the people of Aceh must be immeasurable.

We have been telling people here to take three steps to deal with the possibilities here: 1) don't panic. It is unlikely that anything good will come from irrational behavior. And besides, we are here, so obviously we don't think anything will happen in the immediate future. 2) Know how to flee. Figure out how you will flee to the hills if you feel a very strong earthquake. That will be easy for most of the residents here, because there is a tall hill with many paths right behind the town. 3) Figure out what to do about the long-term problem. Have community meetings to discuss whether to move the town to higher ground or to be willing to accept the losses and rebuild if the shaking and tsunami destroy the town.

10:20 a.m., Tuesday, January 11. On the boat in Sikakap harbor

Yesterday we were able to get to the Perak Batu site and collect the data as planned, but barely got out before dark, and before high tide washed over the helicopter landing pad on the beach. Our friends in the small village were astonished and thrilled to have a helicopter land in front of their little town. Dozens of wonderful, cheering kids and mothers. But the men were off at work in the jungle and didn't come back until about 4:30. They came back early because they saw the chopper land.

The seas are calmer today, so we will be able to depart for Tuapejat, our next site a few kilometers to the north. To conserve helicopter fuel we have decided to download that station by arriving by boat and to have the helicopter leap-frog on to the Sinyang-nyang site on a small island off the south coast of Siberut Island. The boat and helicopter will rendezvous at Malepet, a small harbor on the east coast of Siberut, tonight.

We are delayed this morning, because the local head (camat) and police chief have requested a meeting with us to discuss their concerns about a future earthquake and tsunami. The meeting was supposed to be at 8 a.m., but the ferryboat carrying them from Padang to Sikakap was delayed by the bad weather yesterday. If we don't get out of here until 2 p.m. or so, we'll suffer another day's delay in our plans.

There are many stories to tell of meeting our friends in Perak Batu and here in Sikakap, but the time to write is just too short. Just one short note. My friend Pak Edi has lived at the Wisma Lestari Hotel for 53 years. He says that high tides used to flood the courtyard about once a year. But since the Bengkulu earthquake in 2000, the high tides come into the courtyard every month. I wonder if this indicates merely that the man-made fill of coral rubble settled during the earthquake, or that there was some slow slip on the megathrust outboard of the islands! Too bad our GPS network had not yet been installed in 2000. Actually, Yehuda's network (Yehuda Bock from Scripps) could be resurveyed to see if anything odd happened up here at the time of the 2000 earthquake.

Wednesday morning, January 12. Tuapejat

The boat and helicopter left the harbor at Sikakap, the principal town of the Pagai Islands, at the same time yesterday, as did the TV crew helicopter. They returned to Padang, Sumatra, via Muko-Muko (another town, south of Padang), while we headed north along the east coast of North Pagai, toward Tuapejat, a town of a couple of thousand people on the northern tip of Sipora Island. We are now about two days behind the original schedule.

Bambang Suwargadi, my colleague who handles logistics, and I were to land at the Pulau Panjang GPS site, just a kilometer or so east of the town, and perform the first download of that station. But to our surprise, someone had stolen the receiver, batteries, and solar panel. We spent the afternoon reporting the loss to the Bupati's office (a local official) and then to the police who are in charge of Sipora Island. We asked the Mayor to bring the landowner to see us, so that we could find out the circumstances. Bambang stressed to the authorities that this was the sole instrument on Sipora, so that now we have no way of knowing what is going on beneath the island.

I couldn't reach the boat by satellite phone this morning, but it is safe to assume that they arrived in Malepet (a harbor on the east coast of Siberut Island, to our north) early this morning. The plan is that Bambang and I will download the Sinyang-nyang station off the south coast of Siberut, while the boat team downloads the Saibi station and installs the new telemetry equipment.

We are sitting in a small cafe next to our little hotel. The complex of three buildings has been constructed right on the modern beach, as have dozens of homes and businesses here. I took a photo of one building that tilts toward the sea because the sand under it is being eroded away by the waves. Most of the town is less than a meter (about three feet) or so above sea level. In fact, we've been told before that during very high tides the main street actually floods, like Balboa Island in Newport Beach.

The young couple who live in the room next to ours has three small children. I don't see how they will escape if they are here when a tsunami strikes. It would be fairly easy to construct broad walkways perpendicular to the shoreline up onto the higher ground just behind the town.

Last night I took my usual stroll to clear my mind before turning in for the night. I walked the better part of a kilometer along the main drag, which parallels the beach. The stars were spectacularly bright and the sound of the small surf would have been calming under different circumstances. A group of about 15 fishermen sitting on a porch called me over to join them. They ranged in age from about 18 to 35, I'd guess. They knew that if they felt a big earthquake, they should run for the hills. They said they could get there within 30 minutes. I told them they might have only 15. They didn't know what to do if they were on the water during a big earthquake. So I told them to try to get to deeper water.

10 a.m. Sinyang-nyang site

We left the Bupati's office at Tuapejat about an hour and a half ago, then flew across the Sipora Strait to Nyang-nyang Island. What a beautiful site this is! High on a hill, overlooking the archipelago of small islands off the southeast coast of Siberut Island. We were delighted to see that the instruments are intact and have been recording since we left them in September. We'll finish the download of data at about noon.

A young woman named Martena and two young boys walked up to meet us a few minutes after we landed. She is Thaddeus's daughter. He owned land in this area but was killed by three men last December, because he would not sell the land to someone who wanted to build a resort here. The men are now in custody. The owner of the particular piece of land that the instrument is on is Petros. Bambang will give the maintenance money to Martena to give to Petros.

Two guys in their late 20s and 30s came up toward the end of the three-hour download. They said there had been oscillations of the sea from about 11 a.m. to about 6 p.m. on the day of the earthquake. They say it was low tide when it began, and that the first surge came up about a meter, to near the normal high-tide mark. They didn't know whether the first effect was a withdrawal or a rise of the sea.

10 a.m., Thursday, January 14, en route from Lebuan Bajou to Tello on the big boat

Bambang and I flew from the Nyang-nyang site over the large north-south bay of southern Siberut Island late yesterday morning en route to Malepet, on the east coast of Siberut. It was nearly low tide during our transit, so we could inspect the intertidal zone. Fields of coral microatolls are abundant in the southern third of the bay but the northern two-thirds is a mudflat.

Our big boat had left two 50-gallon barrels of fuel in a soccer field near Malepet, so that we could refuel. We left the helicopter running during refueling, and a large crowd from the community gathered around. I recognized one longhaired character who came up to greet me. He is named Su, and we met here a few years ago, when we were in the area collecting coral samples. He is about 27 or so, and still looking for work. I forgot to ask about the tsunami there.

Continuing north, we flew over vast tracks of virgin jungle, with the double canopy of high, white-barked dipterocarps (tall, rain forest trees) and understory of shorter trees. What a joy to see that so much of the forest here has not been logged by the big timber companies. At least a small part of the Mentawai Islands might yet remain pristine.

We overtook our big boat just 10 kilometers or so south of our next stop, at Muarasaibi. Our equipment is on a hill overlooking this village of several hundred Mentawai people. We've become good friends with many of them, since we first installed the GPS station there. David Satoko is the owner of the land on which the station sits, and he takes extraordinarily good care of the site, keeping the weeds down. He has even built a little bamboo shelter for us during our downloads.

Last August, our friend Tulik, who is from Saibi, showed Caltech's Catharine Stebbins and me the evidence for coastal erosion and submergence in the water in front of the village. I took good aerial shots of the remains of the boardwalk that used to be behind the beach in the swamp, and the freshwater spring that now sits seaward of the beach.

We landed in the soccer field, surrounded by beautiful little wooden homes, including Mr. Surkino, the mayor. After a few minutes of greeting on the mayor's porch, Bambang walked up to the station. I went up with my retinue a little later. The receiver refused to download properly, so we waited for Caltech's John Galetzka, our equipment/logistics guy, to arrive by our small aluminum boat. From the station, we could see that his group was struggling to find the mouth of the river on the delta, a few hundred meters offshore. John couldn't get the receiver to download properly either, so I decided that we would swap it out with a new one. I did not want to leave the troubled receiver there at the site, even though it was recording properly, because that would mean that we had no new data covering the earthquake and post-seismic period. So we went out in our friend Kisman's longboat to the big boat to get a new receiver. This meant, of course, that we would have one less receiver to install on the islands or mainland near the December 26 rupture.

My colleague Danny Natawidjaja stayed on overnight with John at Muarasaibi, but the rest of us boarded our big boat and continued our slow trek to the north. We stayed the night in the harbor of Lebuan Bajau, on the northeastern tip of Siberut Island. We were pleased to hear from John later in the night that he had, after all, been successful in downloading the Saibi station receiver, so there would be no need to use the new receiver there.

We are now on our way across the wide strait between Siberut Island and the Batu Islands to the north. I'm hoping that we can reach Tello, the main town of the Batu Islands, by early afternoon. Then we can download the station there, while Danny and John are downloading the Air Bangis station, on the coast near the Equator, and at Bais, just east of Tello. We plan to rendezvous in Tello, just south of the Equator, tonight.

Our logistics issues (fuel for boat and helicopter and permissions to go into the stricken area) are getting resolved, one by one. Thanks to AceS, the satellite telecom company we are working with, and its CEO, Adi Adiwoso, for satellite phones! And thanks to my friends Christina and Chris Fowler at the Batang Arau Hotel in Padang, and to the Indonesian Institute of Science staff in Jakarta, and Bandung for going to bat for us on all of this. Bambang just learned that we now have a letter from the military that gives us permission to use some of their helicopter fuel.

Bambang is resting below deck now; he suffers from chronic seasickness. I'm feeling a bit nauseated, myself, so I think I'll lie down for a bit, also.

12:56 p.m. A half hour ago, the boat came to a stop. The captain told us that the engine had been leaking oil for the past day and that now there was too little to safely continue on to Tello. So, we are dead in the water here, just inside the south entrance to the long narrow strait between Tanabala and Tanamasa Islands. We can't reach John and Danny via satellite phone to ask them to fly oil to us, so we have sent Bambang and two of the boatmen in our dinghy the 45 kilometers to Tello, where they will buy enough oil to get the boat to Tello. It will be a four-hour round trip, so the boatmen will probably not be back until about 6 p.m. Bambang will stay in Tello to begin to work out other logistical details of the trip.

9:47 p.m. The dinghy has just arrived back from Tello with two, five-gallon containers of oil. Hallelujah, we might make it to Tello yet tonight, if the captain is willing to navigate the straits by the light of the stars. Otherwise, it's four hours beginning at first light. John and Danny got the two stations at Air Bangis and Bais downloaded today, so we have only Tello and Simuk Island, the farthest out and most exposed to the tsunamis, to download here on the islands. Sikuai and Jambi we can do later in the month, after we've finished our business in the earthquake region.

8:30 a.m., Friday, en route to Tello on the big boat

We waited until dawn to resume our trek through the strait and on to Tello; there are too many shallow spots and narrow slots to travel through on a moonless night. I slept in John's hammock on the top of the boat, since he was in Tello last night with Danny and Bambang. They reported by phone at 11 last night that Tello is astir with fears and rumors of another earthquake and tsunami. They spent the late afternoon and evening talking, talking, and talking to individuals and groups about their concerns. Danny confirms that the tsunami there surged into the main street, but that little damage was done. He took notes on the tsunamis at Bais and Air Bangis, based upon eyewitness accounts.

Danny says reports in Tello from Simuk Island are that they also suffered no loss of life from the tsunamis. We breathe a sigh of relief, now, believing that none of our friends appear to have lost their life or property--this time.

I called Heather Guyett Steele, my liaison at Caltech last night at midnight (9 a.m. in Pasadena) and asked her to wire-transfer more money from our accounts there to the helicopter company. We'll need this to reconnoiter Simeuleu and Nias Islands. I doubt that we'll have time to get to the mainland coast before I leave; too many logistical snafus this first week on the islands.

8:00 a.m., Saturday, January 15, Tello, just south of the Equator

Yesterday we made two trips out to remote Simuk Island, the farthest out and most exposed to the tsunamis, yesterday; first Caltech's John Galetzka and Imam left to begin downloading data, then Bambang Suwargadi and I went to measure tsunami heights and talk to the villagers there. The big boat stayed behind in Tello, the main town of the Batu Islands off the west coast of Sumatra, to have its engine repaired--a task that the captain judged would take about three hours.

Simuk is a vast flat island, roughly elliptical in shape, but with three blunt peninsulas jutting meekly west into the Indian Ocean. Huge tsunamis reportedly overwashed much of the island after the giant earthquake of 1861, caused by rupture of the megathrust under Nias Island, just to the north. Flying over the island, one sees vast tracts of coconut plantation, with a few small wisps of smoke rising from burning debris. The highest part of the island is a soccer-field-sized flat hill top about 20 meters (65 feet) above sea level. That is the location we chose a couple years ago for our GPS station.

When John and Imam flew over the Simuk GPS site, they found that the large cleared area around the instrument was covered with temporary shelters. Many families had fled there after the tsunamis of December 26 and were still encamped there. One was just a meter (three feet) or so from the antenna. Last August, we had actually advised them to go to high ground in the event of a large earthquake, but we had no thought that they would encamp there for weeks!

The couple of hundred "refugees" greeted us upon our arrival on the flat hilltop. We held an impromptu meeting, because they were all very concerned about a rumor that had spread among them, namely, that there was to be another large tsunami. To keep order, one leader among them asked for questions, which I answered and Bambang translated.

Then, while John and Imam downloaded data, Bambang and I, and a dozen or so children took the path down the cliff and through the couple of kilometers (mile-plus) of coconut plantations to the village by the sea. We spent about an hour in an impromptu meeting with a few dozen more villagers, organized by Pak Emir (a friend of ours and prominent citizen of Tello, who is in charge of the health services in the area). Everyone wanted copies of our brochure so they could better understand the earthquakes and tsunamis. Many intelligent questions came from people who knew they were at risk from any tsunami that might be larger than the one that washed through about half of their village just three weeks ago. Pak Emir summarized the timing of the tsunami: four ebbs and flows between roughly 9 a.m. (1.5 hours after they felt the earthquake) and 5 p.m., with the ebbs preceding the flows.

Dozens of us then walked down the village street to the beach and found a guy who lived near the beach and was there on the day of the tsunami. Although the waves washed about 100 meters (110 yards) into the village, the evidence for the flood is scant and unimpressive. Based upon this guy's observations, we measured the tsunami height, from sea level just before the tsunami, to the crest of the highest wave: 3.2 meters, or ten feet! The depth of the deepest trough was about two meters.

We arrived back in Tello in the late afternoon only to find that our boat's engine cannot be repaired here in Tello! To make matters worse, all of the new GPS receivers that we were planning to install to the north have now been used to replace defective receivers within our existing network.

So last night we were "dead in the water" again, but with a finality that was pretty depressing, albeit in a beautiful little town and a safe harbor. The Mutiara will have to be towed back to Padang for the repair; the needed parts are not available here. Within the hour, we hatched a new plan: We will split into a GPS crew that will head back to Padang on Monday, the 17th, and a reconnaissance team that will continue north with the helicopter to survey Nias and Simeuleu Islands. We rented a cargo boat here in Tello to carry our helicopter fuel, food, and relief supplies, first to Nias and then to Simeuleu. My two colleagues, Imam and Danny, and I will go north with the new boat (the Rinjani) and helicopter. John, Bambang, and Felix will store all the GPS gear here in Tello and then return to Padang to await the shipment of four new receivers from the U.S. In the meantime they will send the GPS data we have collected back to the U.S. for processing. Danny and I will have the 15th through the 18th to reconnoiter the islands to the north for evidence of uplift or submergence (and to document tsunami heights, as time permits).

Danny and I now await the passage of a large black rain squall that has moved in from the north, before we can take off! Patience is a virtue, I am told.

10:30 a.m., Sunday, January 16, Sinabang, capital of Simeulue Island

Midday yesterday we flew across the Equator to Telukdalam, on the southern coast of Nias Island (itself off the west coast of Sumatra), and near Lagundri bay, a world-famous spot for surfing. My friends Chris and Christina Fowler had sent their boat from Padang, Sumatra, to drop off five barrels of helicopter fuel for us, but we could not find it at the wharf. Anticipating disaster, we called Chris in Padang, who assured us that it had arrived the previous night. He gave me directions to his agent's, Ama Pipir, house, where it would have been stored. By chance I happened to meet Johny, one of Pipir's nephews, just as I was wondering how to get there. He took me on his motorcycle to the house, where it became clear that I had nothing to worry about. Pipir's wife brought me five very delicious mangoes--I ate one, and had a taste of what it must be like in heaven. Saved the rest for the next few days.

Johny and Ama Pipir's family told me they had felt the earthquake Sunday at about 8:30 a.m. and said it lasted about five minutes. The first regression of the water began at 10 a.m. The water did not come back up until 11:30 a.m. Then there were many oscillations, which didn't stop until nighttime. The biggest surge was at 2 o'clock in the afternoon.

We made it to our final rendezvous with the Australian 60-Minutes film crew at Sirombu, halfway up the west coast of Nias. The tsunami damage there was horrific. I felt a bit silly landing in a helicopter, saying a few hellos to the villagers who greeted us, and then immediately starting to work with the film crew. Seemed a bit crass, actually, in the face of all the suffering going on there. I was thankful that we only spent a half hour interviewing and filming, before interviewing villagers and making observations of the tsunami height--about 4.5 meters (almost 15 feet). Only eight villagers died here though, because the big wave hit hours after the first ones arrived, giving all the residents hours of advance notice.

Yamo, a resident of Sirombu, was in Gunungsitoli, the capital city of Nias on the central eastern coast of the island, but told me that his family member Fauzi rode out the tsunami surge in the second floor of his home and is a reliable eyewitness. The big wave came at 4 p.m., and it came from the south, not the north. This must mean that the tsunami reflected off of eastern India and Sri Lanka and came back to the Indonesian islands.

We left Sirombu flying north, reconnoitering the coast all the way to the northern edge of the island. One particularly impressive sight was an entire grove of dead coconut palms sitting out on the reef, seaward of the beach. These obviously had died some time ago, not as a result of the tsunami. They show that the west coast of Nias, like the islands we have been studying farther south, have been sinking during the past several decades. The islands are like a springboard, storing strain for the day when the megathrust below gives way and they spring suddenly back up, producing a great earthquake and tsunami.

We spent the night in Gunungsitoli. Our modest rooms cost us just $5 each! In the evening, I heard amazing stories from the three guys from Telukdalam, a village at the southern end of Nias Island, who had driven our fuel by truck to Gunungsitoli. Alimin is a 52-year-old man who lives on the waterfront in Telukdalam, in a silver-roofed house. He was there when the water came into it, and said the water rose 1.3 meters (four feet, up to his chest) above the floor in his house. The floor of his house is 2.5 meters (eight feet) above low tide. This suggests that the amplitude of the highest surge was about 3.8 meters, or about 12 feet. During the recessions of the sea, the floor of the bay was completely high and dry out to 50 meters (55 yards) from the shore. He and Ama Pipir's son, Handy, estimate the drop was six to seven meters (20 to 22 feet) below sea level! At the time of the tsunami, the sea was near low tide. Handy and his friend Herman were on Ama Pipir's squid boat when the tsunami happened. The boat sank down with the water and came to rest on rocks. They scrambled out and made it to shore before the next surge.

Our new fuel-supply boat arrived at about 4 a.m., and we loaded on the extra fuel barrel that had been delivered by truck from Telukdalam the night before. They took off again for Sinabang ( Simeulue Island's capital) around 11 a.m. It will be a 20-hour trip for them at about seven miles per hour from Gunungsitoli to Sinabang. The same trip took us just 1.5 hours by helicopter late this morning.

We were warmly welcomed by Durmili, the local Bupati (government official) of Simeulue. His assistant, Riswan, was waiting for us at the airport when we landed. We were spirited away to the Bupati's home in the city of Sinabang, where we met a crowd of foreigners who were there for other reasons--medical, media, etc.

We went on a car caravan with the whole crowd, led by the Bupati, to view tsunami damage on the southern part of the southwestern coast. We measured heights of the tsunami of about 2.5 meters (eight feet). All the stories we heard still say that the first indication was a recession of the sea. Also of interest to Danny Natawidjaja, my colleague from the Indonesian Institute of Science (LIPI), and myself was the evidence for small amounts of permanent submergence in these towns. Areas that used to be dry now have up to 30 centimeters (nearly a foot) of standing water in them. Local residents insist that the beaches have eroded ten meters (33 feet) or so since the tsunami.

We heard from the Bupati that word has come from the northern coast that the coral reef there is about a meter (three feet) out of the water. This is almost precisely what Danny and I had been guessing would be the case. We will fly there tomorrow morning to see if the reports are true and, if so, to take some measurements. If the northern part of the island has risen, it means that the southern end of the great megathrust rupture that caused the earthquake is under the island.

At the end of our trip, back at the Bupati's home, we learned from one of the staff that one of the members of our car caravan, Pak Riswan, had lost all four of his children in the tsunami in Banda Aceh, the provincial capital. He was such a stoic all afternoon long. One would never have suspected that the tragedy was also a very personal one for him.

A few minutes ago dozens of people began running up the street past my second-story room, away from the wharf, yelling out to one another. Turns out a rumor of another tsunami had caused them to flee. It didn't even occur to me that was the cause of people running, since I hadn't felt an earthquake. People are clearly on edge here and on Nias Island. So many people ask us if another earthquake and tsunami are coming.

8:46 a.m., Thursday, January 20, en route from Padang, Sumatra, to Jakarta, Indonesia, then on to Singapore

Monday and Tuesday on Simeulue Island were extraordinary, both scientifically and emotionally. On Monday we flew along the southwestern coast, past a score or more of fallen bridges and as many coastal villages, devastated by the tsunami. Near where the island doubles its width we began to see evidence of what looked like an extremely low tide--barren, pale-tan ribbons of coral reef paralleling the coast and extending 100 meters (100-plus yards) and more from the beaches to the waterline.

During our first circling of one of these reef ribbons, we saw striking evidence of emergence--pristine pancake-shaped heads of Porites coral, well above current water level. We landed on the 200-meter wide (700 foot) former shallow reef platform, about halfway between the former sandy beach and the new shoreline. Before we could shut down the engine, 100 or more children and adults swarmed out onto the reef from the trees. We immediately split ourselves into a science team and a relief team; Danny and I began to inspect the corals, while Dayat and Samsir (our pilot and mechanic) began to talk to the villagers and distribute the materials we had brought along as relief aid--clothing, powdered milk, hammers, and fishing equipment.

Even though Danny and I have for the past several years been studying ancient evidence of the slow sinking and fast emergence of the Sumatran coral reefs, we were astonished to find ourselves walking through a pristine marine ecosystem, missing only its multitude of colors, its fish, and its water. Corals of every shape and size rested lifeless on the reef platform--branching corals, massive corals, staghorn corals, fire corals, brain corals, whorls, fans. And here and there a poor crab. Even though the tsunami had raged across the reef, there was scant evidence of any breakage of the delicate whorls and dendritic corals that crunched beneath our feet. But a fishing boat in the trees beyond the shoreline and an overturned, two-ton umbrella-shaped Porites coral heads were testimony to the power of the tsunami. The scene was the marine equivalent of a village on the flank of a volcano after the passage of a nuee ardente (a destructive "glowing cloud")--life quick-frozen in place at the moment of death.

Like us, the villagers quickly segregated into two groups. Most of the adults surrounded Dayat and Samsir, but many of the barefoot children came racing on to Danny and me. Smiling, cheering, boisterous young boys and girls, eager to play with us and to watch what we were doing. We had noticed as we circled the reef that their village, Ujung Salang, had been completely washed over by the tsunami. Hardly a building remained. Yet, there was no trace of sadness in their beautiful faces. I have no idea where they are living now--on higher ground in the forest, I imagine. They were eager to be in the pictures I was taking. In fact, I had to coax them to the sides of the images, so that I could see the corals. I have one picture with several kids standing on top of a pancake-shaped coral head. They are standing at what used to be lowest low tide of the year. At the time of our visit, the water level was a meter (three feet) lower.

We estimate the emergence here to be nearly a meter and a half. To produce so much uplift, the block above the gently northeast-dipping megathrust, 25 kilometers (15 miles) or so beneath the reefs, must have slipped about ten meters (11 yards) toward the southwest.

We hopscotched our way farther north for the rest of the afternoon, stopping only occasionally to make an additional measurement and to divert around rainstorms. A systematic, detailed survey will have to wait until we can return, hopefully in a few months. Along the northern coast, newly emerged reef ribbons were everywhere. The emergence had doubled the diameter of some of the smaller islets. And along most of these coastlines were old stands of decayed coconut palms and other trees out on the reef, seaward of the old beach--testaments to the fact that the land had been sinking slowly in the decades before the earthquake. In the complexly embayed coastline of the northern coast, muddy flats surrounded by mangrove forest have also emerged above the water. Some of these have muddy brown rectangular fields on them. I think these are very old rice paddies that slowly submerged into the intertidal zone or below in the decades prior to the earthquake. Now they are back above high tide, ready for cultivation again! Some villagers have, in fact, asked us if the water will return soon and submerge the newly dried reef and mud flats. We tell them with confidence that submergence of these new lands will not occur soon. It will take more than 100 years for the water to return to its levels on the day before the earthquake.

On Tuesday it was more of the same. We filled some of the gaps between our measurement sites and reconnoitered the northeastern coast. The former lowest low tide level is now at least 25 centimeters (10 inches) above water. So the island tilted coseismically both from northwest to southeast and from southwest to northeast. The pattern and magnitude of uplift is strikingly similar to what we know happened to the south in the Mentawai Islands during the magnitude 8.7 earthquake of 1833. The half-hour flight back south to Sinabang took us over vast tracts of virgin forest, full of tall, white-trunked dipterocarp trees towering over the lush understory. Inspiring flight, tempered only by the fact that Danny and I were a bit uncomfortable in our pants, soaked from our wading in shallow water.

Late Tuesday evening, back in Sinabang, we briefed the Bupati, Darmili, on our findings. We presented him with two gifts from his own island--a small, bulbous, bleached-white head of pristine Goniastrea retiformis (a honeycomb-like coral) from one of the dead reefs and a CD with many of our photographs. He is a gracious and thoughtful man, who seems intent on understanding what has happened, so that he can make good decisions about what to do to help his island recover. We mentioned our interest in establishing a couple of continuous GPS stations on the island, to monitor the "healing" of the earthquake wound. He said he would welcome our return.

Yesterday, Wednesday, we all left Simeulue Island. Danny and Imam flew to Medan, the capital of North Sumatra, on a small commercial airplane, while I flew with the helicopter crew back to Padang, Sumatra. Passing low over the virgin forests and rice paddies of southern Simeulue, it occurred to me that this might well be the most beautiful of all the islands in the chain. We landed twice along the five-hour journey to refuel, at the towns of Gunungsitoli and Airbangis, where we had made sure to stash barrels of fuel for the return flight. At Airbangis, a town almost right on the Equator, an official came to see me while I was waiting in an airy little hotel lobby for the refueling to be completed. He asked for advice about what to do to protect the city. His concerns are warranted: Passing along the coast of mainland Sumatra, between the equator and Padang, we saw ample evidence of the possibility of a repetition of the disaster of December 26. As along the west coast of Aceh, North and West Sumatrans have built many of their villages, towns, and cities right on the coast, directly east of the source of giant earthquakes. In some cases, towns and villages sit on barrier beaches, between the sea and long estuaries. Without the construction of bridges across the estuaries in the coming years, there will be no safe place for the townspeople to flee in the 15 minutes or so between the earthquake and the tsunami surges.

Kerry Sieh

At the end of January, Kerry Sieh left Indonesia for further travel and eventual return to Caltech. Below are reports from his colleague, Caltech's John Galetzka, who remains in the field.

Friday, January 28

Hello all,
Bambang and I swapped receivers at Bais and Simuk Islands and met up with Imam and the hired cargo boat Mentawai Indah in Tello yesterday (Thursday,) evening. We all throttled out of Tello early this morning and have been doing a nice seven knots on our way up to the village of Sinibang on Simeuleu Island. We've been showered on much of the day and currently (Friday night) find ourselves cruising past Gunung Sitoli, Nias Island. We should be in Sinabang late tomorrow morning.

Saturday, January 29

Saturday, 6 p.m. and we have Simeuleu Island in sight. We were delayed by 12 hours because of nasty seas and weather all last night up until 2 p.m. this afternoon. Poor Bambang is very seasick.

We should be getting to Sinabang, Simeuleu, around 10 p.m. this evening. All are looking forward to a nice quiet anchorage tonight and starting GPS station installation tomorrow.

Simeulue Island, Monday January 31

We're ending our second full day here in the area of Sinabang, on Simeulue Island. We started building a GPS station at the island's only airport today after getting the thumbs up from the island's chief administrator yesterday. The station should be up and running by tomorrow at noon, February 1. That includes satellite telemetry with the latest version of satellite terminal firmware from the ACeS team in Batam, Indonesia.

Bambang and I also gave a talk tonight at a gathering of island officials and foreign guests. We had no clue it was going to be such a formal event! Lobster and other delicacies for dinner, desert, and famous Aceh coffee. Thankfully our graphics and our message made up for me failing to wear long pants!

We plan to place a station near Sinabang first, followed by a station on the northern coast of Simeulue, then one somewhere near Banda Aceh. The Nias station will be last because we're expecting two receivers sent by Heather and others at Caltech, to be delivered to the Bupati's office in Gunung Sitoli.

Great news! The police in Tuapejit located all the equipment stolen from the Panjang Island station. The police are expecting that reward Kerry promised!

Other great news: there are about 30 less cockroaches on our ship due to my fancy footwork of the last 24 hours!

Wednesday, February 2, on Simeulue Island

Hello all,
Our fine ship and crew are all now on the extreme northern tip of Simeulue Island, anchored in a cove near a village called Lewah. This morning we left Sinabang, the island's capital on the east coast, on a late start (electric generator issues, I think) and cruised the east side of the island on our way north. I slept in late this morning to catch up on rest, but during this time my colleagues Bambang and Imam met up with the Bakosurtanal (equivalent to the USGS) that will be re-occupying Yehuda and Jeff's site (both from the Scripps Institute) here in northern Sumatra. I think our timing to install the new GPS station at Simeulue Airport in order to support this latest survey couldn't be better!

As we approached the northern coast of Simeulue, we started looking for potential GPS sites. Around 4 p.m. I spotted some hills that would nicely accommodate a GPS station. What made things better was that it was near Lewah, with its sheltered cove for the ship, and we still had a couple of hours to hit the shore, chat with the locals, and scout out a specific place for the GPS station.

Lewah took a direct hit from the earthquake and subsequent tsunami. Amazingly, no one, not one single person, was killed. The locals said the shaking was strong--no one could stay standing!--and lasted about two minutes with a separation of about 10 seconds between the primary and secondary earthquake waves. Once the shaking stopped, everyone ran for the highest points possible on the hills behind the village. The first wave of the tsunami train was a positive wave (where the initial tsunami wave is a crest, causing a rise in water level). Villagers across the bay said they saw a huge wave gathering offshore of Lewah, but then it broke unexpectedly several hundred meters (a few hundred yards) before hitting the village. The center of the village was hit with a surge of water about one meter (three feet) deep, but it is amazing how much of the village is intact.

The villagers indicate that sea level has dropped between one and two meters, and pointed to the exposed reef in front of the former beach as evidence. Bambang and I take all this to mean that this part of the island experienced uplift. The uplifted reef probably reduced the force of the tsunami blow considerably. There are coral micro-atolls all over the place. Some still have living tissue at their bases, while other, older ones have been exposed in their sandy graves by the December tsunamis.

We'll take time over the next few days to not only build a continuous GPS station here, but also document post-seismic uplift and tsunami parameters. We'll listen and record the stories of the villagers, hand out some relief supplies, and give a presentation tomorrow night on the science behind the earthquake and tsunamis they witnessed.

Friday, February 4, Northernmost Point of Simeulue Island

Hello to all,
There is another operational continuous GPS station on Simeulue Island as of this afternoon, Friday, February 4, 2005. The station is named after the nearby village, Lewak (the station code is LEWK), which is located on the northernmost promontory of the island. We planted the station on one hot, sunny, and steamy day, and boy, are we smoked! I was expecting afternoon thundershowers today just like the previous days, but I was fooled. I did feel a small earthquake this afternoon instead, its shear waves lasting about five seconds.

We will spend the whole day tomorrow interviewing the villagers about their earthquake and tsunami experiencesÑsorry, just had an interruption. The boat crew just caught a sea turtle by accident (a hook in its left front flipper). I yelled at them in all the excitement to let it go, but finally had to go down and grab the thing out of their hands and throw it back into the night. Half the guys wanted to make a stew out of it.

Now, as I was saying, we will spend tomorrow doing interviews, making more measurements of uplift based on coral and mangroves, and taking lots of photos. I can tell you a few key things we have learned so far:

--Uplift in this area (N 02.924*, E 095.804*) is around 35 centimeters (almost 14 inches).

--The first tsunami wave (a positive, where water rises) hit about 30 minutes after the earthquake; a second tsunami hit about 20 minutes later and was larger than the first. Smaller tsunamis kept coming even into the evening.

Last night's outreach program was attended by many people, including those from nearby villages. We set up an outdoor theater using a projector screen, digital LCD projector, laptop computer, amplified sound system, and a portable electric generator. First, Bambang and I congratulated them for doing an excellent job of surviving the earthquake and tsunamis. Then we showed them a picture of a nine-meter (29 feet) offset across a stream along the Denali Fault in Alaska, a cross-sectional drawing of a typical subduction zone, tectonic maps of Southeast Asia, Caltech's Chen Ji's finite fault model, satellite images of devastated areas on Sumatra, and videos of tsunamis hitting Sri Lanka, Thailand, and Banda Aceh. We gave them a quick course on plate tectonics and the nature of tsunamis. The program was a hit and lasted until 10:30 p.m., which is pretty late for a remote little village.

Well, that's it for tonight. I hope to provide a longer report tomorrow.
John Galetzka and the Team

Wednesday, February 9

Hello folks,
Sorry for the communications blackout. We've been busy. Real busy.

Currently anchored in a river near a village called Lamno in western Aceh on Sumatra Island. The third station has been installed as of late this afternoon. The name is Ujung Muloh (Muloh Point), UMLH, approximate coordinates N 05*03', E 095*,20'. The rock was hard and the day was hot. We woke at 0530 hours to work on the station, and just ended (2330 hours) an evening program at the village about earthquakes and tsunamis.

The impact of the tsunamis between here and our last stop, Banda Aceh, is just unbelievable! Every meter of coastline has been swept. Low-lying areas that I've seen are two to three kilometers (one to two miles) inland. Headlands and cliff shorelines are washed clean an average of about 15 meters (16 yards), and in some places we have seen evidence of waves reaching 30 meters.

Recovery is in progress and relief helicopters are everywhere. Survivors of the tsunamis are trying to start their lives again and hold what's left of their community together. I've only seen one person crying since I've been in Aceh. We spoke to one young man today that used to live in a house not too far from where we built our GPS station. He was away at college when the waves came. They took away his entire family, all the homes and buildings in the village, along with at least 90 percent of its inhabitants.

The crew is splitting up tomorrow: Bambang, my colleague, a television crew, and I are flying by helicopter back to Banda Aceh where Bambang and I will catch a commercial flight to Medan (Sumatra), then Gunung Sitoli on Nias Island; the rest of the team will take our cargo boat, the Mentawai Indah to Gunung Sitoli on Nias Island, via Sinabang on Simeulue Island.

I'm off to my hammock for four hours of sleep.

Friday, February 11

Bambang and I are currently delayed in Medan, Sumatra, for a day, taking a forced rest break before meeting up with the boat on Simeulue Island. We will head for Nias Island after troubleshooting some equipment.

I walked around Ujung Muloh (Muloh Point), in western Aceh on Sumatra Island the morning after completing the GPS station. It's not difficult to measure the tsunami runup. It is, however, difficult as hell to measure tectonic subsidence or uplift. I have never encountered anything like the landscape the team and I have been running around in these last few days here on the mainland Aceh province. The erosion caused by the tsunamis is immense. The senses are near saturation as you wander around shallow graves, drifts of debris, and polished house foundations looking for evidence of pre-earthquake sea level.

I focused on taking as many photos as possible during my two-hour survey of the east side of Muloh Point. My hope was to capture subtle clues that I could see after careful review and thought.

I can say with almost certainty that this area experienced co-seismic subsidence. How much? Whew, that's tough to say, but my estimate is about 25 to 50 centimeters (ten to 20 inches). Perhaps there was more, but that requires more work walking the site with knowledgeable survivors, and reviewing photographic surveys of the Ujung Muloh bridge that the provincial road department might have.

Another observation: the chance for survival on the islands of the forearc ridge (a forearc is the region between a subduction zone and a volcanic chain) is higher because high ground tends to be close to villages; here on the mainland, populations are larger and tend to congregate in broad coastal plains where there is little chance to outrun a tsunami, even with a few minutes of warning.

I am convinced that our base city, Padang, West Sumatra, as it exists now, will one day meet the same fate as the western coast of Aceh. For the last few years I thought that tsunamis generated by a giant earthquake under the Mentawai Island might cause havoc 100, 200 or even 300 meters (100 to 300 yards) into Padang. From what I've seen in Banda Aceh and Ujung Muloh, a two- kilometer (mile-plus) tsunami runup into West Sumatra coastal plains is assured. Let's hope there is time to change the way people live in cities and villages in coastal areas of western Sumatra.

Off to bed.

John Galetzka

February 12-18

Dear colleagues and friends,

This is the final report from the field here in Sumatra. The LIPI team, crew of the Mentawai Indah, and I are back safe in Padang, West Sumatra province after spending 23 days at sea, on various islands, and the west coast of mainland Aceh province. We overcame fears of additional tsunamis, outbreaks of disease, encountering Free Aceh Movement (GAM) rebels, and traveling into new and uncertain waters. To make the best use of our time and money we didn't limit our sea travel time to daylight hours. We covered long distances at night, encountering many violent thunderstorms along the way--thank goodness for GPS.

We succeeded at our primary goal of installing four continuously operating GPS reference stations around the southern portion of the giant December 26, 2004 rupture on the Sumatran subduction zone. The team managed to do a few other useful tasks as well:

--Resolving bad GPS hardware problems at two older GPS stations en route to the epicentral area.

--Supporting efforts by our partners at Asia Cellular Satellite (ACeS) in testing satellite telemetry at three GPS stations.

--Conducting quite a bit of educational outreach in the form of evening multimedia programs explaining the science behind the earthquake and tsunamis to government officials and the public in various villages and towns.

--Doing an equally large amount of educational outreach on earthquake and tsunami preparedness at our stopovers to islands outside the devastated area.

--Making a handful of observations of tectonic vertical displacement, and tsunami size, timing, polarity, and runup of water.

--Interviewing a few selected individuals about their experience of the earthquake and tsunamis to be used for future educational outreach materials.

--Handing over a small amount of relief supplies to two villages (Lewak and Lamno) directly affected by the tsunamis that are hosting new GPS stations (I really wish we had more to give).

Please allow me to backtrack one week to tell you some of our adventures. I believe I last reported to you on February 12 from Medan, North Sumatra province. At that time my colleague Bambang and I had split from the boat to try to fly ahead of them to do some advance work on Nias Island. Medan was also an opportunity to catch a little rest, take in some excellent food, and send out some emails and GPS data files over a rare broadband Internet connection.

February 12

Early morning Bambang and I failed to get a flight to Nias Island, but we lucked out when Imam called from Sinabang, Simeulue Island, to say that the boat had made a slight detour to fill up on fresh water for showering and cooking. We caught a rickety old cargo-turned-passenger plane to Simeulue, fixed (temporarily) the GPS station at the airport, then linked up with the boat in Sinabang harbor. We were off to Nias Island a little before noon.

Note: No one in Sinabang, including the harbor master or myself, has observed any recent change in sea level at the harbor, approximate coordinates N 2.486*, E 96.386*.

February 13

Arrived and anchored a kilometer off shore from Gunung Sitoli, Nias Island, very early in the morning during another nasty thunderstorm. Once the sun and a reasonable hour of Sunday morning came around, Bambang and I went to meet with the vice chief administrator of Nias to get permission to install a GPS station on the northwest tip of Nias. We received a positive response and even the use of a driver and 4x4 vehicle to scout for a site.

Several hours later with the help of some very friendly locals, a site was found on a coconut palm-covered limestone plateau near the town of Lahewa. Bambang and I zipped back to Gunung Sitoli for a quick bite to eat, to tell the boat crew that we would be leaving Gunung Sitoli at 1 a.m. to cruise around to Lahewa, and to give our earthquake/tsunami briefing to the Augus, the vice chief and a media specialist he hired from Medan to make an educational video for the public about the tsunami hazard on Nias.

February 14

12 a.m. wakeup call, then 1 a.m. departure from Gunung Sitoli, navigating by GPS counter-clockwise around the island to get to Lahewa. As usual, we encounter another wicked thunderstorm along the way, but somehow manage to make our appointment with a cargo truck at the Lahewa harbor at 7 a.m.

By 9 a.m. the Hilti drill was driving the 2.25 millimeter drill bit into the weathered limestone, while coconut palms were falling left and right at the hands of a man with a big chain saw making suitable skyview for the GPS station. The day was already punishingly hot and humid, and the sky was filling with a thick smoke haze from forest and agricultural fires in eastern Sumatra.

6 p.m. and the station was turned on and tracking satellites, the local helpers paid, and the tools loaded on the hired truck. Dinner (typically fish curry and rice) was served back at the boat, followed by a quick email message via satellite, to Caltech's Kerry Sieh and Jean-Philippe Avouac, then to sleep around 10 or 11 p.m.

February 15

After a quick early morning check of the new GPS station and an interview with Jim, the harbormaster, we trotted off to Tello Island. The haze limited visibility to about three kilometers and blocked our view of the west coast of Nias Island. Kerry and Danny were lucky not to have encountered this atmospheric situation during their helicopter survey of Nias and Simeulue back in January. It is an especially dry year here in Sumatra, but with all the thunderstorms we bump into, one might be surprised to hear such news.

Note: Mr. Jim, the harbormaster here in Lahewa, Nias (N 1.397*, E 97,172*), was witness to the tsunamis of December 26, 2004 that entered this two-kilometer long, mangrove-lined bay. He indicates that a 50- centimeter (foot-and-a-half) tsunami with positive polarity arrived around 8:52 a.m. local time (about one hour after the earthquake). A second surge of similar height arrived around 11:06 a.m. The third tsunami was the largest and caused minor havoc in the harbor. That surge arrived around 1:35 p.m. and was about 1.7 meters (about six feet) above average sea level. There were smaller tsunamis throughout the evening. There were no deaths attributed to the tsunamis in Lahewa, but several fishing vessels were destroyed.

February 16

3 a.m. and I wake to the sound of yelling. "KIRI, KIRI, KIRI!" (LEFT, LEFT, LEFT!), followed by a big crunching sound. I fly out of my hammock and started stuffing a drybag with laptop computers, satellite phones, and other small valuable items. After traveling hundreds of kilometers in unfamiliar seas over the past couple of weeks, the captain hit a reef less than one kilometer (half-mile) from the dock at Tello Island, a place he is supposed to be very familiar with. The ship was tilted up slightly and 15 degrees to the left. Gunning the engine in full reverse and dumping the freshwater stored in the forward tanks did nothing to move the boat off the edge of the reef--all we could do was hope that the tide was going up.

This is not the first time I've been on a boat that has hit coral, but this was certainly the hardest impact. I always wonder where these crazy boat captains come from and how they are selected to be boat captains. It seems to me that they are almost always the least sensible person on the boat crew.

I took this time before higher tide and the arrival of the burning sun to visit the Tello GPS station to upgrade the ACeS satellite terminal firmware. I was hoping that by the time I arrived at the boat dock, the Mentawai Indah would be freed from the reef and waiting for me. It was still dark when I arrived back at the boat dock with the boat off in the distance still perched on the reef. At 7 a.m. we fired up the engine again and pulled on a rope to an anchor set 50 meters (55 yards) left and to the rear of the boat. We broke free!

Imam snorkeled under the boat trying to look for damage but found nothing serious. With that good news we started for our next destination 13 hours away--Muara Saibi, Siberut Island.

February 17

Not surprisingly, just after midnight and one hour away from Muara Saibi, we headed straight into another damn thunderstorm in our course. Imam had navigated us up to this point using GPS, but now it was my turn to guide us into the bay in darkness and rain. After dropping anchor, the dingy dropped me just outside the surf zone at Muara Saibi--in the dark, we weren't sure how big the surf was and didn't want to put the dingy at risk taking me to the beach. Wading through the surf turned out to be easy, as was finding the trailhead on the beach. Fifteen minutes later I was at the GPS station swapping out GPS receivers.

By 4 a.m. I was back on the Mentawai Indah. The next destination was Sikuai Island, a resort near our home port in Padang.

It was 3 p.m. as we neared Sikuai Island and the dramatic headlands in this part of West Sumatra. The scene reminded me of the coast of Aceh, minus the zone near sea level stripped bare by the big tsunamis. The guest center and all the bungalows at the resort would fit within this zone that was no less than 15 meters (50 feet) high. We have a GPS station perched on a hilltop there at Sikuai, and the staff knows us very well. They said that there was a "strong" earthquake a few days prior and that everybody ran up the hill in fear of tsunamis.

February 18

I checked a USGS earthquake website back in Padang the next day and didn't find an earthquake greater than magnitude 5 anywhere near this area. Like elsewhere in Indonesia, people are very nervous about another big earthquake and tsunami.

The police on Sipora Island caught three individuals and recovered the hardware stolen from the GPS station at Panjang Island. Bambang examined the recovered items at a police station in Padang--the geodetic monument, radome (antenna housing), and GPS antenna seem to be unharmed back at the site. Only the solar panels and batteries can be used again--the GPS receiver was dismantled by the individuals who tried to figure out what the gizmo was used for.

Imam called from the small boat harbor to tell us that the side of the Mentawai Indah that struck the reef had developed big leaks. The boat was going to get a zinc sheet band-aid, then head for a dry dock in Sibolga, North Sumatra for full repair.

Well, that's all. The field team is tired, but happy for this experience. We hope our efforts are helpful to mankind. Appreciation goes out to the various support elements in Padang and Bandung, Indonesia, and in Pasadena and La Jolla, California.

John Galetzka
Field Assistant
Tectonics Observatory
California Institute of Technology

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