Yu, W;
Lin, J;
Su, J;
Song, TA;
Kang, C;
(2020)
S ‐coda and Rayleigh waves from a decade of repeating earthquakes reveal discordant temporal velocity changes since the 2004 Sumatra Earthquake.
Journal of Geophysical Research: Solid Earth
, 125
(7)
, Article e2020JB019794. 10.1029/2020jb019794.
Preview |
Text
Song_2020JB019794.pdf - Published Version Download (6MB) | Preview |
Abstract
Temporal changes in the subsurface seismic velocity structure reflect the physical processes that modulate the properties of the media through which seismic waves propagate. These processes, such as healing of the surface damage zone and deep crustal deformation, are described by similar functional forms and operate on similar timescales, making it difficult to determine which process drives the observed changes. We examine earthquake‐induced velocity changes using the measured lag‐time time series τ (t ) of the repeating earthquake sequences since the 2004 M w 9.2 Sumatra and 2005 M w 8.6 Nias earthquakes. The S coda velocity changes (δV S, equivalent to −τ S) recover steadily during the 2005–2015 period. The Rayleigh wave velocity changes (δV LR, or −τ LR) undergo transient recovery, followed by a strong δV LR reduction in late 2007. δV S recovery is most likely driven by deep processes, whereas the temporal breaks in δV LR recovery in 2007 mostly reflect surface damage and healing induced by the strong ground motions of the 2004 M w 9.2, 2005 M w 8.6, 2007 M w 8.4, and M w 7.9 Bengkulu and 2008 M w 7.3 Simeulue earthquakes. The observed differences between the temporal variations in δV S and δV LR can distinguish deep processes from healing of the surface damage zone.
| Type: | Article |
|---|---|
| Title: | S ‐coda and Rayleigh waves from a decade of repeating earthquakes reveal discordant temporal velocity changes since the 2004 Sumatra Earthquake |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1029/2020jb019794 |
| Publisher version: | https://doi.org/10.1029/2020JB019794 |
| Language: | English |
| Additional information: | This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/10098098 |
Archive Staff Only
 |
View Item |
