Publication Date:
2020-11-24
Description:
Apparent stress and corner frequencies are measured for the Chi-Chi, Taiwan
sequence beginning with the Mw 7.6 mainshock on 20 September 1999. Using the
coda source ratio method, we obtained stable source ratio estimates using
broadband stations on Taiwan. We find the following: (1) For the mainshock and
3 of the larger aftershocks, apparent stress is clustered around 0.8 MPa (+/-
0.1 MPa); (2) Events below ~Mw 5.5 exhibit lower apparent stress with larger
scatter, ranging between ~0.08 and 0.8 MPa and are spatially variable; 3) The
Brune [1970, 1971] omega-square source model fits the spectral shape for events
4.7〈Mw〈7.6, however a step-wise break in self-similarity exists at ~Mw 5.5. We
hypothesize that larger events are subject to the regional state-of-stress,
whereas smaller aftershocks are sensitive to the local state-of-stress from
stress-field redistribution following the mainshock and/or fault zone
lubrication that affects only larger events.
Description:
Published
Description:
L10308
Description:
3T. Sorgente sismica
Description:
JCR Journal
Description:
reserved
Keywords:
earthquake fault dynamics
;
apparent stress
;
dynamic stress drop
;
04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
