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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


Volltext §
DOI: 10.5445/IR/1000126138
Veröffentlicht am 04.02.2021
Cover der Publikation
Zugehörige Institution(en) am KIT Geophysikalisches Institut (GPI)
KIT-Zentrum Klima und Umwelt (ZKU)
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
Schlagwörter Megathrust earthquake, seismic tomography, subduction zone, aftershocks, Ecuador
Referent/Betreuer Rietbrock, A.
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