Publication Date:
2012-02-03
Description:
We study the 2003 Mw 8.1 Tokachi‐oki earthquake, a great interplate event that
occurred along the southwestern Kuril Trench and generated a significant tsunami. To
determine the earthquake slip distribution, we perform the first joint inversion of tsunami
waveforms measured by tide gauges and of coseismic displacement measured both by
GPS stations and three ocean bottom pressure gauges (PG) for this event. The resolution
of the different data sets on the slip distribution is assessed by means of several
checkerboard tests. Results show that tsunami data constrain the slip distribution offshore,
whereas GPS data constrain the slip distribution in the onshore zone. The three PG data
only coarsely constrain the offshore slip, indicating that denser networks should be
installed close to subduction zones. Combining the three data sets significantly improves
the inversion results. Joint inversion of the 2003 Tokachi‐oki earthquake data leads to
maximum slip values (∼6 m) confined at depths greater than ∼25 km, between 30 and
80 km northwest of the hypocenter, with a patch of slip (3 m) in the deepest part of the
source (∼50 km depth). Slip values are very low (≤1 m) updip from the hypocenter.
Furthermore, the rupture does not extend on the plate interface off Akkeshi. As a
significant back slip amount (∼4 m) has accumulated there since the last 1952 earthquake,
this segment could rupture during the next large interplate event along the Kuril Trench.
Description:
Published
Description:
B11313
Description:
3.1. Fisica dei terremoti
Description:
JCR Journal
Description:
open
Keywords:
tsunami
;
coseismic displacement
;
joint inversion
;
05. General::05.01. Computational geophysics::05.01.03. Inverse methods
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
