A catalog of coseismic uniform-slip models of geodetically unstudied earthquakes along the Sumatran plate boundary
Abstract
The Sumatran plate boundary has experienced five Mw > 8 great earthquakes, a handful of Mw 7-8 earthquakes and numerous small to moderate events since the 2004 Mw 9.2 Sumatra-Andaman earthquake. The geodetic studies of these moderate earthquakes have mostly been passed over in favour of larger events. We therefore in this study present a catalog of coseismic uniform-slip models of one Mw 7.2 earthquake and 17 Mw 5.9-6.9 events that have mostly gone geodetically unstudied. These events occurred close to various continuous stations within the Sumatran GPS Array (SuGAr), allowing the network to record their surface deformation. However, due to their relatively small magnitudes, most of these moderate earthquakes were recorded by only 1-4 GPS stations. With the limited observations per event, we first constrain most of the model parameters (e.g. location, slip, patch size, strike, dip, rake) using various external sources (e.g., the ANSS catalog, gCMT, Slab1.0, and empirical relationships). We then use grid-search forward models to explore a range of some of these parameters (geographic position for all events and additionally depth for some events). Our results indicate the gCMT centroid locations in the Sumatran subduction zone might be biased towards the west for smaller events, while ANSS epicentres might be biased towards the east. The more accurate locations of these events are potentially useful in understanding the nature of various structures along the megathrust, particularly the persistent rupture barriers.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.G43A0918W
- Keywords:
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- 1207 Transient deformation;
- GEODESY AND GRAVITY;
- 1211 Non-tectonic deformation;
- GEODESY AND GRAVITY;
- 8159 Rheology: crust and lithosphere;
- TECTONOPHYSICS;
- 8163 Rheology and friction of fault zones;
- TECTONOPHYSICS