Session: Science, Hazards and Planning in Subduction Zone Regions [Poster]
Type: Poster
Date: 4/25/2019
Time: 06:00 PM
Room: Grand Ballroom
[Withdrawn] Repeating Earthquakes Record Fault Weakening and Healing Following a Megathrust Earthquake
Repeating earthquakes (REs) rupture identical fault patches allowing variations in the mechanical behavior of specific areas to be interrogated over the earthquake cycle. We study several families of repeating earthquakes that reveal fault weakening after a large earthquake in Costa Rica followed by fault recovery. We find shorter RE recurrence intervals and increased RE rupture areas immediately following the large earthquake that both gradually return to pre-earthquake values. This is consistent with other studies and the interpretation that an increase in post seismic loading rate speeds up the time to RE failure and drives conditionally stable regions surrounding REs to slip unstably increasing their rupture areas. However, unlike most other observations that report an increase in post seismic RE magnitudes (expected if RE rupture areas increase), our postseismic REs show no change in magnitude. This requires a reduction in RE slip that we interpret as evidence of fault weakening. This is consistent with experimental work showing slip amplitudes and stress drop decrease with loading rate.
Presenting Author: Esteban J. Chaves
Additional Authors
Esteban J Chaves esteban.j.chaves@una.cr Volcanological and Seismological Observatory of Costa Rica, Heredia, , Costa Rica Presenting Author
Corresponding Author
|
Susan Y Schwartz syschwar@ucsc.edu University of California, Santa Cruz, Santa Cruz, California, United States |
Rachel E Abercrombie rea@bu.edu Boston University, Boston, Massachusetts, United States |
[Withdrawn] Repeating Earthquakes Record Fault Weakening and Healing Following a Megathrust Earthquake
Category
Science, Hazards and Planning in Subduction Zone Regions