Consecutive Ruptures on a Complex Conjugate Fault System During the 2018
Gulf of Alaska Earthquake
- Shinji Yamashita
, - Yuji Yagi,
- Ryo Okuwaki,
- Kousuke Shimizu,
- Ryoichiro Agata,
- Yukitoshi Fukahata
Shinji Yamashita
University of Tsukuba, University of Tsukuba, University of Tsukuba, University of Tsukuba
Corresponding Author:luxemburg1386@gmail.com
Author ProfileYuji Yagi
University of Tsukuba, University of Tsukuba, University of Tsukuba, University of Tsukuba
Author ProfileRyo Okuwaki
University of Tsukuba, University of Tsukuba, University of Tsukuba, University of Tsukuba
Author ProfileKousuke Shimizu
University of Tsukuba, University of Tsukuba, University of Tsukuba, University of Tsukuba
Author ProfileRyoichiro Agata
Japan Agency for Marine-Earth Science and Technology, Japan Agency for Marine-Earth Science and Technology, Japan Agency for Marine-Earth Science and Technology, Japan Agency for Marine-Earth Science and Technology
Author ProfileYukitoshi Fukahata
Kyoto University, Kyoto University, Kyoto University, Kyoto University
Author ProfileAbstract
We developed a flexible finite-fault inversion method for teleseismic P
waveforms to obtain a detailed rupture process of a complex
multiple-fault earthquake. We estimate the distribution of potency-rate
density tensors on an assumed model fault plane to clarify rupture
evolution processes, including variations of fault geometry. We applied
our method to the 23 January 2018 Gulf of Alaska earthquake, setting the
model fault area to fit the distribution of aftershocks occurring within
one week of the mainshock. The obtained source model, which successfully
explained the complex teleseismic P waveforms, shows that the 2018
earthquake ruptured a conjugate system of N-S and E-W faults. The
spatiotemporal rupture evolution indicates irregular rupture behavior
involving a multiple-shock sequence, which is likely associated with
discontinuities in the fault geometry that originated from E-W sea-floor
fracture zones and N-S plate-bending faults.
