Funded
in part by
NSF grant 0538333
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May 16 , 2005:
Kerry leaves Jakarta for Sumatra to join his technical and scientific
crew who are already there, preparing for their journey.
Thursday, May 19, 2005:
Kerry and John leave Jakarta by helicopter; the rest of the crew
follows by boat out of Padang. All are heading for Tello, the
capital of the Batu Islands just a few miles south of the equator.
Friday, May 20, 2005:
On to southern Nias, where they encounter spectacular evidence
of submergence along the southeastern coast: rows of coconut
palms have been eroded and swept away by the surf since the earthquake.
Wednesday, May 25, 2005:
Amid a whirlwind of activity, with two field teams going out each
day to survey changes to the coastline and the boats motoring
to the next port along the coast, Kerry finds time for an update.
Thursday, May 26, 2005:
Heading for the politically sensitive Banyak Islands,
Kerry and crew are not sure what to expect as they prepare to
check in with local authorities.
Friday - Monday, May 27-30, 2005:
Spectacular evidence of recent uplift and submergence,
captured in great photos as the team surveys Simeulue Island.
Tuesday, May 31, 2005:
A National Geopgraphic film crew follows the Caltech team
as they continue their work and begin to get a sense from the
people on Simeulue, what it was like to be some of the first
to feel the great earthquake of December 2004.
Wednesday, June 1, 2005:
At a small island north of Ujung Salang, off the west
coast of Simeulue, the newly exposed reef is already growing
grasses, a village destroyed by the tsunami is being rebuilt,
and Kerry hears a hairraising story of a fishing boat flung into
at tree by the powerful waves.
Friday, June 3, 2005:
Miscommunication between ground team, helicopter, and
the cargo boat, leaves three team members stranded for the night
in a small town on the west coast of Simeulue.
Saturday, June 4, 2005:
Last night in the field. An unexpected highlight; striking
evidence of liquefaction of the delta sediments at the mouth
of a small river on the north coast of Nias. |
We have three goals for this month-long
journey in the parts of Sumatra affected by the two recent big earthquakes:
First and foremost, we want to continue and to complete measurements
of the crustal deformation that occurred during those giant ruptures
of the Sunda megathrust. These measurements will be important
for understanding how much and where the megathrust moved during
both of the earthquakes. We started to do this in mid-January
and found that the northern half of Simeulue Island had risen
up to 1.5 meters and had tilted toward the Sumatran mainland
and toward the southeast.
Now, with the March 28th earthquake, we have about 10 times as
much coastline to measure uplift along! And we have places that
are submerged as well. The extent of the March 28, 2005 rupture
is based on what we have gleaned from eyewitness accounts of
uplift and sinking as well as on initial interpretations of seismograms
and our GPS data. Let’s see how good a job we’ve
done figuring it out before we see it for ourselves!
Second, we want to install a few seismic instruments in the region
of the 1797 and 1833 giant earthquakes, because we want to be
ready to collect important seismic data if that section should
break in the next few months or years. We have six seismometers
from Professor Clayton and four accelerometers from professors
Heaton and Clayton and Ken Hudnut of the USGS, Pasadena office.
Third, we have some repairs to make to some stations in our GPS
network.
-K.S. |
Thursday,
May 19, 2005:
After nearly a week of running around Jakarta acquiring various research
and travel permits and in Padang stocking our boats with equipment,
supplies and food, the crew is assembling tonight in Tello, the capital
of the Batu islands, just a few miles south of the Equator. John
and I have been traveling up from south Sumatra via helicopter over
the past two days, while the rest of the crew has been motoring up
from Padang over the past day in two boats: The cargo boat that is
carrying 33 barrels of fuel for the helicopter and the passenger
boat carrying the rest of the gear.
Traveling up the Mentawai
islands by helicopter has allowed us to make minor repairs
to the GPS stations on the Pagai islands and to install two
new seismic stations on the islands (at Silabu and Nyangnyang
and two on the mainland (Air Bangis and Sikuai), without delaying
greatly our mission in the earthquake areas. At the island
stations we have had the usual enthusiastic receptions from
our local friends (Photos 1-3).
#1 #2
#3
We’ve told them the latest
results from the GPS instruments that they have been attending – they
moved a centimeter or so south during the Nias-Simeulue earthquake
on March 28th.
After we buried the seismic sensors a meter
into the ground, we ask the local kids if they want to make an
earthquake. We get them to jump up and down and count the number
of jumps. Then we let them look at the monitor and count the
spikes, so they can see that they’ve made that many "earthquakes."
Many, many people in the island villages and towns are still quite
afraid that a big earthquake and tsunami might hit them. They know
from our educational efforts that unlike the Aceh and Nias sections,
the Mentawai section of the subduction megathrust has not yet ruptured
to produce a giant earthquake. The hills around some villages are
dotted with aluminum sheeting and orange and blue plastic tarps
that are the roofs of small “pondoks,” make-shift structures
where they have been either living full-time or spending the nights(Photo
4).
#4
In most cases the villagers tell us that they
built these because they fear a big tsunami like those that have
hit their neighbors to the north. But in a few cases, they have
misinterpreted the title of the first version of our educational
poster (“Our islands are sinking because of earthquakes”)
to mean that the islands will sink during a great earthquake! Of
course, the posters were created before the Aceh-Andaman earthquake,
and that title was aimed at getting local people to listen to
our warnings by first pointing out something that they already
knew -- that their islands were slowly sinking and that this
was part of the earthquake process. The drowning of jungle
trees and orchards and the steady sinking of wharfs over the
decades were things that many, many people on the islands new
about and wondered why they were happening. Fortunately
the number of islanders who have misunderstood the pre-earthquake
message of the posters and brochures are a small percentage of
the populace. Nonetheless, we have taken some criticism for our
choice of words in the pre-earthquake materials. |
Friday, May 20, 2005:
Today we flew across the Equator to southern Nias and began work
along the southeastern coast. The evidence for submergence of the
land at Fanedanu village, our first stop a few tens of miles north
of Telukdalam, is spectacular: Row after row of coconut palms has
been eroded and swept away by the surf since the earthquake. And
a lighthouse now sits about 20 meters offshore, with the waves crashing
around its concrete pillar foundations (Photo 5).
The villagers say that before the earthquake it was about 20 meters
inland. Along most of the coast in front of their village they
say the sea has eroded about 50 m landward. Much of the village’s
livelihood came from selling copra from the coconut palms, so they
are having trouble now making enough money to keep themselves fed.
The tsunami of March 28th flooded the land about 250 meters inland
from the current coastline and the Dec 26th tsunami flooded only
about 50 meters short of that. But the village is about 400
meters inland, so it was unflooded. In our walk through the village,
we saw dozens of ancient stone carvings (Photo 6).
One wonders whether or not the inland location of the village has
to do with lessons learned 140 years ago, when the giant 1861 earthquake
devastated the island. As far as shaking damage is concerned, only
a few homes and part of the concrete-block church collapsed. It is
clear that steel reinforcing kept the church from complete collapse
and that a bit of steel connecting one wall to another would have
kept all the walls up.This morning in Tello, we hired a pedicab driver
who Bambang had used before (Photo 7). He is a young
man about 25 years old, I would guess. Over breakfast at Amir’s
house this morning, Bambang told us this story: About 5 years ago,
the guy was making a living as a driver between his hometown in Myanmar
and Thailand. On one trip to Thailand, he went with an expired passport.
The Thai police arrested him and sold him to a Thai fishing boat.
They enslaved him and 6 other Myanmar men as fishermen and sailors
for 2 years. He told Bambang that if men got sick on the boat, they
were initially given medicine to see if they would get better. If
that didn’t work, they were thrown overboard, either alive
or after being murdered. One day they made port at Tello, and there
the 6 Myanmar men escaped and ran into the hills, emerging only after
the Thai boat had left the harbor. Amir and his family took the guy
in and have helped him find a way to make a living. Now he owns two
passenger pedicabs and one cargo pedicab and has saved about $100,
which he hopes to use to get back home to Myanmar. Just a couple
months ago, Bambang delivered a letter from him to his family in
Myanmar, in which he told them he was still alive and trying to earn
enough money to get back home. |
#5
#6
#7 |
Wednesday, May 25, 2005:
The past several days have been a whirlwind of activity,
with two field teams going out each day to survey changes to the
coastline and the boats motoring to the next port along the coast.
So, there has been no time to spare to write. Today we are lying
at anchor in the harbor at Gunungsitoli, taking time to resupply
and rest a little. Several days ago, at Lagundri bay, the famous
surfing spot on southern Nias, we measured an uplift of about 80
cm, using the old and new levels of green algae on a concrete wall
that extends into the sea (Photo 8). A little
farther north, we found about the same result, on a newly exposed
reef littered with large coral blocks encrusted with dead mussels. |
By the time we arrived at Sirombu, a
little town about half way up the west coast of Nias, we were measuring
uplifts of more than two meters. The beach in front of Sirombu is
now very broad. And at the harbor, most of the long wharf is out
of the water and the end of the wharf is so high above the water
that it can no longer be used (Photos 9 and 10).The
tsunami in March was small, compared to the one in December, even
though the source of the latter was much farther away than the source
of the former. The March tsunami reached only to the seawall at the
wharf. Thus it appears that the large uplift basically counteracted
the height of the tsunami. Lavenda, a small island just to the
south, is now about 10 times its former size and the former shallow
reef is now out of the water (Photos 11 and 12).
A new beach is forming on what used to be the outer edge of the shallow,
subtidal reef. The water receded from the reef fast enough that crabs,
reef fish and octopuses had too little time to escape, for their
remains were common on the dried sea floor (Photo 13).
Or, perhaps the concussion of the earthquake waves stunned them and
left them unable to move. A bit of a miscommunication among
ourselves led to half of us spending Saturday night on the porch
of a home at Sirombu harbor. The guys on the boat understood that
we were supposed to meet in the Hinako islands, miles offshore from
Sirombu. The rest of us thought the agreement was to meet up in Sirombu.
We waited for the boats to arrive, with most of our personal gear,
dinner and our bunks, but for naught. An hour or so after dusk, a
family at the harbor offered us a small meal and company on the porch
of their home, while we waited. The woman who cooked for us had lost
her home in the December 28th tsunami. When it became clear that
our boats were not going to arrive, the family offered the use of
their well for bathing. The water level has dropped a meter since
the earthquake, to a level 4 meters below the floor of the room.
The rope on the bucket is now very long! We talked until 9 or so
and then they spread woven mats on the porch for us to sleep on.
Hordes of mosquitos made sure that no one slept very well there.
In the Hinako islands on Sunday, we measured uplift in several places.
Steve, who runs the surfing resort on Asu, the northernmost of this
cluster of small islands, welcomed us when we landed on the beach
nearly in front of him. He and his staff were eager to learn what
we could tell them about the reasons for the earthquake and tsunami
and, more importantly, what might the future bring. He has been living
and surfing on Asu for about a quarter century, so he knows the reefs
well. He reported that the rocky reefs there were never above water
before the March 28th earthquake. Now they are permanently above.
The surfing waves have changed, some for the worse, but some for
the better. Sunday night, we anchored off the east coast of
Wunga island, near the northwestern tip of Nias. Twelve years ago,
when I had just begun to explore the earthquake story of the islands,
the fishing boat we had hired took us into the big beautiful blue
lagoon that fills most of the center of this C-shaped island. |
#8
#9
#10
#11 |
It was there that I first donned mask
and fins to explore the reef with my friend and colleague, Fred Taylor.
The back of the “C” is on the west and the opening is
on the east. I remember that an elderly man there told us that his
grandfather had taught him that in 1907 a large tsunami had washed
across the island from the west, cutting it in two. Twelve years
ago, one could in fact see there were shallow gaps in the back of
the “C,” across which waves would wash at high tide.
The island is now more than half barren reef, inset into which are
the half dozen or so small green islets that once formed the C-shaped
cluster. The bay has shrunk from uplift to a fraction of its former
size (Photos 14 and 15). We anchored offshore of
the opening, because it is now too shallow to enter. Uplift here
is about two meters. Yesterday, we started to work east along the
northern coast of Nias island. Measurements from the emerged corals
near the town of Lahewa are yielding uplifts nearly as great as that
recorded by the GPS station that Galetzka and crew installed in February – nearly
3 meters. What the corals can’t give us are the horizontal
motions during the earthquake. People here are astonished to learn
that the GPS instrument recorded more than 4 meters of motion toward
the southwest during the earthquake.
As we suspected, though, the uplift diminishes rapidly toward the
east to zero near the northeastern tip of the island. Here at Gunungsitoli,
on the east coast of the island, the change in elevation is so slight
that it is not easy at first glance to tell whether the land has
sunk or risen. |
#12
#13 |
#14 #15 |
Thursday, 26 May 2005:
Today we began to explore the Banyak islands, closer to the Sumatran
mainland and between Nias and Simeulue islands. We chose to meet
in what we thought was Balai, the capital of the region, in order
to check in with the local authorities. We had never been to any
of these islands before and were aware of their political sensitivity.
But the town we landed in, on the northern coast of Tuangku, the
largest of the islands, is Haloban, not Balai. Half way through our
inspection of Haloban, we were ordered to immediately fly east to
Balai to report in. Both there and at Haloban, we had a warm reception
from leaders and residents.
Throughout the region, evidence for submergence is clear. Mangrove
forests fringing the coasts show massive mortality (Photo
18). Haloban and Balai have both sunk so much that waterfront
roads are canals during high tides and buildings stand partially
submerged (Photos 19 and 20). At Haloban, a waterfront
coconut grove is now flooded and, in fact, a new beach is forming
within the grove (Photo 21). At both Haloban and
Balai, refugees from flooded waterfront homes are building shelters
in public areas around grassy playing fields (Photo 22).
The great community spirit in these places is clear; everyone is
helping the less fortunate. Despite the immense challenges of reconstructing
their livelihoods with little support from the outside world, most
are in good spirits. The young men commonly come out to watch us
survey the amount of submergence (Photo 23).
#21 & #22
We went into the town tonight, during low tide, and enjoyed hanging
out with some of our boat crew and new friends at a pleasant outdoor
shop and café.
At Balai, Rich and I measured watermarks from today’s high
tide as high as 74 cm above the water level in the street. We saw
one home in which people were still living, where they had re-built
their beds higher off the floor, so that they wouldn’t have
to move during high tides. The woman of the house was sweeping
the floor of debris that had washed in during the morning’s
high tide.
Before returning here to Haloban for the night, we finished off
the day’s work by flying to the westernmost of the islands,
Bangkaru, where we measured uplift ranging from about 70 cm in
the west to about 20 cm in the east. The western site has beautiful
old snags on the reef, which indicate that in the decades prior
to the earthquake the island was slowly submerging (Photo
24).
The raised outer rims of the coral microatolls tell the same story – slow
sinking of the island before its sudden uplift during the earthquake.
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Friday, 27 May 2005:
Sinabang harbor is a sight to behold; what remains of the concrete
dock sags enormously and the pilings are covered with dead encrusting
marine organisms that no longer are submerged enough to have survived (Photo
25). Boats are laden with scrap metal from the destroyed
buildings here and are delivering their cargo to the mainland. Relief
ships are still arriving. At the airport, the modest terminal building
collapsed and has already been replaced by a smaller, lighter structure.
In January, I was amazed to see so little damage from the first big
earthquake to structures along the road from the town to the airport.
Now I am amazed at how much damage has been wrought by the second,
smaller big earthquake. Structures are damaged or down everywhere. The
hotel in which we stayed in January burned to the ground after the
earthquake, along with most of the buildings in the neighborhood. |
#25
|
Saturday, 28 May 2005:
#26 & #27
#28 & #30
|
Today Aron, Nug and I measured uplift on the small islands west
of Simeulue (Photos 26 and 27).
To my surprise, the uplift does not increase westward; rather
it is only about half the 1.7 m our GPS station recorded at the
Simeulue airport. I wonder if this means that the megathrust
did not fail all the way out to the trench. If so, this might
help explain the relatively small size of the March 28 tsunami.
In Busong bay today, on the west coast of Simeulue, just south
of our GPS station, we came across a small island that had emerged
during the earthquake (Photos 28 and 30).The
evidence was clear that prior to the earthquake, high tides had
submerged all but the snags of a few dead coconut palms there.
Kids and young men came swimming or canoeing over to see us.
A local fellow, Arsen, told us that his family had farmed the
coconut grove on the island since at least 1950 and that as recently
as 1985, some of the trees had still been alive. I told him that
they could replant, since the island would take another century
or so to sink back beneath the waves! |
Sunday, 29 May 2005:
So, unlike the southeastern coast of Nias, which submerged on March
28th, the eastern coast of Simeulue has risen. Today both survey
teams measured emergence along this stretch of the coast. In one
large, murky, mangrove-lined bay, Nug, Aron and I found a family
of coral microatolls that clearly shows emergence about two years
before emergence during the March 28th earthquake (Photo
31). Most likely this is evidence of the November 2002 M
7.4, which we now recognize was a precursor to both giant earthquakes
and appears to have occurred precisely between their rupture planes.
|
#31
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Monday, 30 May 2005:
We’re overnighting in Telukdalam, tonight, the central of three
large bays along the eastern coast of Simeulue. Quiet here, without
the harbor sounds of Sinabang. Just the lights of a home a couple
hundred meters away at a small dock.
More evidence for uplift as we proceeded today farther north up the
eastern coast of Simeulue island. The changes in the landscape are
spectacular, but they are everywhere and everyday, so we are becoming
used to the spectacular! More old drowned coconut groves now
out of the water (Photo 32), more islands now connected
across barren new ground (Photo 33), more beautiful
dead corals (Photo 35), more reefs now starting
to support the growth of grasses and small trees (Photo 34).
#32#33
#34#35
We began working today with a film crew that is preparing a program
for National Geographic. They are pretty much just filming us while
we are doing our thing. Those times where they need to stage our
activities in order to get a good sequence feel a bit awkward to
me. It seems a bit stupid to climb in and out of a helicopter three
times in front of a crowd of villagers while the film crew gets the
footage they think they need. Oh well, no harm done I suppose;
people here probably already think we’re a bit strange, spending
so much time walking over the reef and making measurements. |
Tuesday, 31 May 2005:
Today, I particularly enjoyed a time that the NG crew filmed
with four local fishermen who paddled over to the helicopter
as it sat waiting for us on a little beach. By the time I had
swum over from our survey site across the mouth of a little
bay, our pilot Machfuld, was translating between director,
Simon, and the fishermen. Simon was asking them really good
questions about their experiences during the earthquakes and
tsunamis. They were saying that they were frightened that their
world had become so uncertain in the past few months. Things
they had thought so reliable, the sea and the landscape, had
changed, and they were worried that there might be more changes.
Simon asked them if they thought it would help if they knew
more about why the earthquakes and tsunamis had happened, and
they responded enthusiastically in the affirmative. It was
a natural opening to drag out the few copies of the new Nias-Simeulue
poster that I’d brought along. So, they filmed us talking
about the reasons for all these changes. The fishermen seemed
relieved to hear that it takes many decades or longer for the
earth to prepare for an earthquake and that without a big earthquake,
another tsunami is exceedingly unlikely.
Tonight we are anchored in the small harbor of Lewak, a small
village on the northeastern tip of Simeulue island and the closest
habitation to the epicenter of the December 26th earthquake.
One of the four new GPS sites that we established after the first
earthquake is on the hill just above the town (Photo
36). |
In the photo you can see the cargo boat that is
carrying all our helicopter fuel. Next to it the small fishing boat
that the NG crew rented for an arm and a leg to help them get around.
Their “fixer,” the Indonesian guy who made their arrangements,
told them it would be fully outfitted for them and that it slept
ten. We are wondering if he was referring to people or to chickens! We
have loaned them blankets and mats and invited them to dine with
us and use our toilet and shower facilities, as the little fishing
boat has none of these things.
When we landed at Lewak late this afternoon, we got the usual warm
greeting from dozens of men, women and children. In addition, though,
one old man was so grateful for our presence that he kissed both
Aron and myself on both cheeks! |
#36 |
Jean-Philippe and our French crowd
in the Tectonics Observatory would feel right at home here. These
villagers would have been the first in the world to feel the beginnings
of the giant earthquake that would in the following minutes and hours
change so many lives around the Bay of Bengal forever. Imam recorded
a video of their interview in early February of a man who saw, from
the hill, the tsunami bore roil into the bay here.
Tomorrow morning, we plan to cut one of the dead coral microatolls
on the reef platform on the other side of town. John and Imam found
some particularly beautiful ones when they visited here to install
the GPS station here last February. The NG crew was particularly
interested in filming this aspect of our research, so Dudi and crew
have dusted off the chain saw, engine and waterpump and carted it
to the boat from Bandung. Cutting a slab now will give us a
chance to see whether or not there were any anomalies in sea level
changes in the decades prior to the earthquake. |
Wednesday, 1 June 2005:
Tonight we’re anchored on the protected side of the small island
north of Ujung Salang, on the west coast of Simeulue. Rich, Danny
and Nug used the helicopter to hop from reef to reef along the northern
coast of the island, measuring uplift, while the rest of us remained
behind to cut the coral at Lewak. We’ve rendezvoused here,
minus the NG crew, who started motoring back to Sinabang along the
east coast early this afternoon. They need to catch their plane out
tomorrow morning.
We cut a nice slab of coral this morning at Lewak. Several men helped
us lug the equipment the few hundred meters through town to the reef
and to lug it and the sample back to the boat (Photos 38
and 39).
Today we realized that all the uplift along the northern coast, between
Lewak and Ujung Salang, occurred during the December earthquake.
The guys have found no differences between Danny’s and my measurements
in January and today’s measurements (Photo 41).
We have now shown that the December and March uplifts overlap only
slightly and that there is a clear saddle in the uplift values between
the uplift regions of the two giant earthquakes.
Here at Ujung Salang the emerged reef has matured appreciably in
the four months since Danny and I visited. Grass has begun to grow
on the reef platform and even on the tops of some of the coral microatolls.
I wouldn’t be surprised if within ten years the whole reef
is covered in grasses, shrubs and small trees. It will be interesting
to see if the farmers replant coconut groves on the new ground. And
there is a new beach forming on the edge of the newly emerged coastline. Photo
42 shows the new beach strand along the new coastline. The
old village, in the trees on the left was almost completely destroyed
by the December 26th tsunami; a new town is being built against the
hill on the right. The lines of trees above the new village are a
clove orchard.The fishing boat that we saw in the trees last January
has been carried out onto the reef and is nearly repaired and ready
to return to the sea. How they are going to get it over the 1.5-m
high new beach is a mystery to me. Will they shovel a path through
it or just brute-force the ship over it? The captain of the boat
came over to ask me for a “souvenir,” that is a handout.
I asked him where he was during the tsunami that carried the boat
into the trees. I was amazed to hear him say that he was on the boat
and rode out the tsunami on it. He described how the sea first sucked
him out as it receded. The sea then came back at him as a 5-meter-high
foaming bore, which he headed directly into and managed to ride over
it. He and the ship were sucked back out and sent back in again twice.
The third wave carried the boat into the woods and left it there.
Do I believe this story? Not sure.
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Friday, 3 June 2005:
Well, last night Aron, Nug and I were abandoned by the helicopter
and thought we would end up spending the night in a small town half-way
up the west coast of Simeulue. Machfuld had been shuttling both survey
crews southward along the coast in a leap-frog manner all day. By
mid-afternoon he needed more fuel, so he headed south to our pre-arranged
anchorage for the night, Busong bay. Unfortunately, the cargo boat
had gotten the wrong information about the rendezvous point and was
nowhere to be seen. It didn’t arrive ‘til about 5:30,
so the fuel couldn’t be gotten into the helicopter until just
before dark. So the helicopter had to stay put for the night.
We had no way of knowing this of course, so we just passed the time
shooting the breeze with a crowd of local guys who had come out to
find out what we were doing. When we all had gotten a little hungry,
an hour or so before sunset, one of the younger guys fashioned climbing
gear out of two pieces of tree bark and climbed one of the coconut
palms to retrieve a half dozen coconuts (Photo 43). |
#43 |
By six thirty we knew we’d not
be getting back to the ships by helicopter and began discussing our
options with our new friends. They offered to find a friend who had
a car and drive us back the 3 or so hours to our boat; or they would
ask the village mayor to house us for the night.
As we sat in a small two-room home, lit by a lone kerosene lamp,
we talked about the earthquakes and tsunami and how it had unsettled
their lives. Our expressed opinions that a repetition of the giant
earthquakes there was not likely for decades or longer calmed them
and they were thankful for our explanations and opinions. About seven
thirty or eight a young guy came by with a pickup and we began Mr.
Toad’s Wild Ride through the countryside. I rode up front with
Ikbar, our 20-something driver; Nug and Aron rode in the bed of the
truck. Ikbar had been living in Meulaboh at the time of the
earthquake and tsunami of December 26th. Of the 100,000 or so inhabitants,
he and his parents were among the 25,000 or so to survive. He said
that he and his parents had been taught about the 1907 Simeulue tsunami
and knew to run for the hills when the sea withdrew after the earthquake.
Today we were joined by another film crew. These two guys, Edwin
and Roeland, are from a production company that is doing a piece
for Discovery Channel. In the morning they filmed us cutting two
corals from the small island in the middle of the bay and did a little
bit of flying around for their benefit. Rich, Danny and Nug used
the helicopter in the morning to finish up our measurements here
on Simeulue.
Tonight both boats leave on the long trip back down south to Nias,
expecting to reach Gunungsitoli tomorrow mid-day or so. I’ll
stay with Machfuld, Edwin and Roeland at a surfer’s house
on shore tonight. We’ll fly down to Nias tomorrow morning and
spend the day filming. |
Saturday, 4 June 2005:
Last night in the field, anchored here in Gunungsitoli harbor again.
Aron and Rich, Imam and Nug will stay on to finish up measurements,
especially in the Banyaks, where we have only two measurements to
constrain the pattern and magnitude of submergence.
The highlight for me today was our stop at a small village at the
mouth of a small river on the north coast of Nias. Flying over a
couple weeks ago, I had seen striking evidence of liquefaction of
the delta sediments, so I thought this might be a rather spectacular
place to film the effects of a large earthquake. Hundreds of light
gray sandblows dot the fields just outside the town (Photo
44).
These are a common occurrence on the loose, saturated sandy sediments
at the mouths of rivers. Residents told us the fountains of water
and sand began about half-way through the shaking of the March 28th
earthquake and that water continued to flow up to four days afterwards.
In the town, which sits on the west side of the river, large fissures
opened up and wrecked many of the houses and the mosque (Photo
45 and 46).
Our last stop of the day was at Onolimbu, a town on the easternmost
tip of Nias, and also at the mouth of a river. There was no obvious
evidence of liquefaction there, but compaction of the river sediments
had caused much of the town to settle down into the intertidal zone.
Much of the town is now flooded during higher tides and some homes
and former beachfront has actually slumped meters down beneath the
sea (Photo 47). |
#44
#45
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#46 #47 |
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