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Recent Crustal Deformation in West-Central South America

Citation

Pritchard, Matthew Earl (2003) Recent Crustal Deformation in West-Central South America. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/XADN-C411. https://resolver.caltech.edu/CaltechETD:etd-06022003-105512

Abstract

I use interferometric synthetic aperture radar (InSAR) to create maps of crustal deformation along the coast and within the volcanic arc of central South America. I image deformation associated with six subduction zone earthquakes, four volcanic centers, at least one shallow crustal earthquake, and several salt flats. In addition, I constrain the magnitude and location of post-seismic deformation from the afore-mentioned subduction zone earthquakes. I combine InSAR observations with data from the Global Positioning System (GPS) and teleseismic data to explore each source of deformation. I use the observations to constrain earthquake and volcanic processes of this subduction zone, including the plumbing system of the volcanoes and the decadal along strike variations in the subduction zone earthquake cycle.

I created interferograms of over 900 volcanoes in the central Andes spanning 1992-2002, and found four areas of deformation. I constrained the temporal variability of the deformation, the depth of the sources of deformation assuming a variety of source geometries and crustal structures, and the possible cause of the deformation. I do not observe deformation associated with eruptions at several volcanoes, and I discuss the possible explanations for this lack of deformation. In addition, I constrain the amount of co-seismic and post-seismic slip on the subduction zone fault interface from the following earthquakes: 1995 Mw 8.1 Antofagasta, Chile; 1996 Mw 7.7 Nazca, Peru; 1998 Mw 7.1 Antofagasta, Chile; and 2001 Mw 8.4 Arequipa, Peru. In northern Chile, I compare the location and magnitude of co-seismic slip from 5 Mw > 7 earthquakes during the past 15 years with the post-seismic slip distribution. There is little post-seismic slip from the 1995 and 1996 earthquakes relative to the 2001 event and other recent subduction zone earthquakes.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:earthquakes; InSAR; radar interferometry; South America; subduction zones; volcanoes
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geophysics
Minor Option:Planetary Sciences
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Simons, Mark
Thesis Committee:
  • Kanamori, Hiroo (chair)
  • Stevenson, David John
  • Simons, Mark
  • Gurnis, Michael C.
Defense Date:12 May 2003
Record Number:CaltechETD:etd-06022003-105512
Persistent URL:https://resolver.caltech.edu/CaltechETD:etd-06022003-105512
DOI:10.7907/XADN-C411
ORCID:
AuthorORCID
Pritchard, Matthew Earl0000-0003-3616-3373
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:2375
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:10 Jun 2003
Last Modified:10 Feb 2021 23:36

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[img] HTML (Table of calderas in the central Andes with links to interferograms of each) - Supplemental Material
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