A year ago, John Suppe provided internet links to fascinating stuff re last
September's big earthquake in the Taiwan thrust-and-fold belt. For those
who may still be interested, this is just a further update.
The link to Katsuyuki Abe's fantastic images of surface breaks etc is still
active:
http://wwweic.eri.u-tokyo.ac.jp/topics/taiwan/photo.html
One of these shows a neat fault-bend fold in grass-covered alluvium,
developed where the fault scarp cuts across a track-and-field stadium, from
which we can infer that the dip of the footwall ramp is ~25 degrees.
The link to J C Lee's maps of the seismic gap is no longer active, but
these maps and other good stuff can now be browsed at
http://www.earth.sinica.edu.tw/921/921chichi_main_eng.htm
First-motion studies of the aftershocks indicate oblique-slip displacement
on hangingwall tear-faults at either end of the thrust-faulted block.
There is also a neat GPS-displacement map of Taiwan between 1992 and 1998.
The link to Yugi Yagi's teleseismic computations of slip distribution is
still active:
http://wwweic.eri.u-tokyo.ac.jp/yuji/taiwan/taiwan.html
On his series of "snap shots" of the moment-release process, up-dip
propagation from the epicenter appears to be followed at t~11.5 seconds by
triggering of a separate shock ~20 km down-dip to the southeast, and at
t~14.5 seconds by triggering of the biggest shock ~20 km north of the
epicenter. This behavior contrasts with that of last November's big
earthquake in Turkey, where the energy release appears to propagate
smoothly up dip and along strike in both directions:
http://wwweic.eri.u-tokyo.ac.jp/yuji/trk/izumit.html
Cheers, Dugald
Dugald M Carmichael Phone/V-mail: 613-533-6182
Dept of Geological Sciences and Geological Engineering
Queen's University FAX: 613-533-6592
Kingston ON K7L3N6 E-mail: [log in to unmask]
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