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3D Tomography based on the aftershock sequence of the 2016 Mw 7.8 Pedernales, Ecuador earthquake

León-Ríos, Sergio

Abstract (englisch):
Based on seismicity recorded by the permanent Ecuadorian seismic network and our large emergency network installed shortly after the 2016 Mw 7.8 Pedernales earthquake, I derive a seismic 3D velocity model for central coastal Ecuador based on local earthquake tomography (LET). I manually analyzed seismic waveforms recorded on our combined amphibious network to determine high quality arrival times of seismic phases. I inverted the seismic travel times simultaneously for earthquake locations and three-dimensional (3D) velocity structure ($Vp$ and $Vp/Vs$) using a staggered approach that increases complexity from 1D to finally obtaining a detailed 3D model.

While our 1D velocity model highlights the first-order structures of the studied margin through the analysis of the relocated seismicity, station correction terms and regional moment tensors (RMT), the resulting three-dimensional tomographic images show an area that is widely affected by the subducting topography and small- to large-scale faults at the surface. The oceanic Nazca plate is well imaged down to $\sim$40 km depth by an eastward dipping high $Vp$ velocity feature. I also identify a low $Vp$ ($\sim$5.5 km/s) region along strike in the marine forearc, which I interpret as a thermal anomaly that might be caused either the rocks coming from the Galapagos Hot Spot or by shallow serpentinization. ... mehr

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Volltext §
DOI: 10.5445/IR/1000126138
Veröffentlicht am 04.02.2021
Cover der Publikation
Zugehörige Institution(en) am KIT Geophysikalisches Institut (GPI)
Publikationstyp Hochschulschrift
Publikationsdatum 04.02.2021
Sprache Englisch
Identifikator KITopen-ID: 1000126138
Verlag Karlsruher Institut für Technologie (KIT)
Umfang xvi, 144 S.
Art der Arbeit Dissertation
Fakultät Fakultät für Physik (PHYSIK)
Institut Geophysikalisches Institut (GPI)
Prüfungsdatum 30.10.2020
Referent/Betreuer Prof. A. Rietbrock
Schlagwörter Megathrust earthquake, seismic tomography, subduction zone, aftershocks, Ecuador
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