Seismic velocity reduction and accelerated recovery due to earthquakes on the Longmenshan fault

Various studies report on temporal changes of seismic velocities in the crust and attempt to relate the observations to changes of stress and material properties around faults. Although there are growing numbers of observations on coseismic velocity reductions, generally there is a lack of detailed...

Full description

Saved in:
Bibliographic Details
Published in:Nature geoscience 2019-05, Vol.12 (5), p.387-392
Main Authors: Pei, Shunping, Niu, Fenglin, Ben-Zion, Yehuda, Sun, Quan, Liu, Yanbing, Xue, Xiaotian, Su, Jinrong, Shao, Zhigang
Format: Article
Language:English
Subjects:
704/2151/508
704/2151/562
Acceleration
Asperity
Earth and Environmental Science
Earth Sciences
Earth System Sciences
Earthquakes
Fault lines
Geochemistry
Geology
Geophysics/Geodesy
Healing
Inversions
Material properties
Reduction
Seismic activity
Seismic response
Seismic velocities
Temporal variations
Travel time
Velocity
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Various studies report on temporal changes of seismic velocities in the crust and attempt to relate the observations to changes of stress and material properties around faults. Although there are growing numbers of observations on coseismic velocity reductions, generally there is a lack of detailed observations of the healing phases. Here we report on a pronounced coseismic reduction of velocities around two locked sections (asperities) of the Longmenshan fault with a large slip during the 2008 M w  7.9 Wenchuan earthquake and subsequent healing of the velocities. The healing phase accelerated significantly at the southern asperity right after the nearby 2013 M w  6.6 Lushan earthquake. The results were obtained by joint inversions of travel time data at four different periods across the Wenchuan and Lushan earthquakes. The rapid acceleration of healing in response to the Lushan earthquake provides unique evidence for the high sensitivity of seismic velocities to stress changes. We suggest that stress redistribution plays an important role in rebuilding fault strength. After a fault ruptures, the recovery of its strength may be accelerated by earthquakes that redistribute stress, according to an analysis of temporal variation in crustal seismic velocity on the Longmenshan fault in China.
ISSN:1752-0894
1752-0908
DOI:10.1038/s41561-019-0347-1