Resolving Seismic Locations and Ground Deformation from Coseismic and Large Aftershock InSAR Images of the 2016 Pedernales Ecuador Earthquake Sequence
Abstract
Coseismic surface deformation of the April 16, 2016 Pedernales Ecuador earthquake (Mw 7.8) is observed using SAR interferometry (InSAR) from descending tracks of the Sentinel-1A satellite. The InSAR images can reveal the large scale ground deformation in the satellite's line-of-sight (LOS) direction, shaken by a large-magnitude earthquake, while the aftershocks reported from the National Earthquake Information Center (NEIC) in this sequence are mainly distributed seaward of the trench (updip) and extend 100 km southwest from the mainshock epicenter. Large coseismic displacements are located south from the mainshock epicenter in an area of little aftershock activity. A Sentinel-1A descending pass was also acquired between the times of the two largest aftershocks (Mw 6.7 and Mw 6.9) 9 hours apart on May 18, 2016 and their epicenters are located within a region of transition between high and low coseismic deformation. We invert for coseismic surface deformation from separate Sentinel-1A InSAR images of the mainshock and the two May 18 aftershocks using a single fault Okada model. Double-difference relocation (teletomoDD) of aftershocks using phase information from the NEIC catalog is computed to compare relative locations of the seismicity with the InSAR models and observations. We evaluate whether the source locations derived from InSAR observations for large aftershocks in this sequence can be established as `ground truth' locations and if they are comparable with the absolute and relative source locations from seismic data.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.T54C..06K
- Keywords:
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- 8104 Continental margins: convergent;
- TECTONOPHYSICSDE: 8118 Dynamics and mechanics of faulting;
- TECTONOPHYSICSDE: 8123 Dynamics: seismotectonics;
- TECTONOPHYSICSDE: 8170 Subduction zone processes;
- TECTONOPHYSICS