Tsunami models courtesy
Jose Borrero, Tsunami Research Center, University of Southern California
Press
Release Scientific
Paper
This is the entire
region scenario, which is caused by 20 meters of slip on the entire
Mentawai patch (nearly 800 km long), with slip extending from just
east of the islands all the way up to the trench. First, you see
the initial deformation of the sea surface related to the rupture
of the megathrust -- about 6 meters of uplift southwest of the
islands, about 2 to 4 meters under the islands, and subsidence
of about a meter at Padang (on the coast at about 1 degree south)
and 2 meters at Bengkulu (on the coast at about 3.8 degrees south).
As the movie runs, you see the orange bulge propagate both southwestward
and northeastward. In this view, you can't see much detail of the
tsunami at any particular spot. Download
movie
Detail
of what happens at Padang (population about 800,000, between about
0.9 and 1.0 degrees south) on the mainland coast. The sea retreats
until about 25 minutes after the earthquake. Then within the next
ten minutes, the first crest arrives. It reaches a height of about
5 meters. The next wave crest arrives at about 55 minutes and is
also about 5 meters high. Download
movie
Prognostications for Bengkulu (about
350,000 people, around 3.8 degrees south). Before the movie starts
you see the coseismic deformation pattern -- a 3-meter trough in
the sea surface is just offshore. As the movie runs you see that
there is very little withdrawal of the sea after the earthquake,
but that the trough arrives at the tip of the peninsula at 3.8 degrees
about 13 minutes after the start of the earthquake. The sea begins
to rise there about 19 minutes after the start of the earthquake.
By thirty minutes, it has risen to about 7 meters and that level
is sustained for about 10 minutes. By one hour, another trough has
arrived. Surprisingly, at about 2 hours, another big wave arrives.
It travels down the coast and reaches heights of about 7 meters,
also. Notice the characteristics of the tsunami north of the peninsula,
in the two large river drainages at about 3.75, 3.77 and 3.79 degrees.
The inundation distances (the distance the waters flow overland)
are enormous -- several kilometers. Download
movie
