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Investigating past and present continental earthquakes with high-resolution optical imagery

Over the past few decades, remote sensing has emerged as a powerful tool for studying active faulting in continental regions. However, the commonly used remote sensing techniques, including radar interferometry, visual inspection of imagery, and image matching, cannot measure three-dimensional (3D) surface displacements in earthquakes, limiting our ability to investigate faulting. The improvement of very high-resolution (VHR) optical imaging systems (stereo in particular) in recent years has made it possible for earth scientists to measure 3D surface deformation remotely. In this thesis, I contribute to assessing the capability of VHR optical imagery, by determining earthquake deformation from four different types of earthquakes (different in sense of slip and date of the event). In the case of the 2010 M<sub>w</sub> 7.2 El Mayor-Cucapah, Mexico earthquake, I show that digital elevation models (DEMs) derived from Pleiades stereo imagery are comparable to light detection and ranging (LiDAR) surveys, and differencing pre- and post-earthquake DEMs can measure 3D displacements, which will be very useful for studying future earthquakes. For the 2013 M<sub>w</sub> 7.7 Balochistan, Pakistan earthquake, I determine the vertical motion from a post-earthquake Pleiades DEM and find constant fault kinematics throughout the Late Quaternary. This study has resolved a current controversy of the Balochistan earthquake, in which it has been argued that kinematics of the Hoshab fault switches between strike-slip and dip-slip. Applying historical aerial, KH-9 Hexagon spy satellite, SPOT-2 and modern SPOT-6 images to the 1978 M<sub>w</sub> 7.3 Tabas-e-Golshan earthquake, I measure the coseismic and postseismic displacements, and show that the Tabas fold system in eastern Iran may exhibit characteristic slip behaviour. Combining Pleiades imagery, fieldwork and geological dating techniques, I determine slip in the 1556 Huaxian earthquake in China and the recurrence interval for similar events. These examples demonstrate the usefulness of high-resolution optical imagery in investigating past and present earthquakes.

Identiferoai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:730473
Date January 2016
CreatorsZhou, Yu
ContributorsWalker, Richard ; Parsons, Barry
PublisherUniversity of Oxford
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Sourcehttps://ora.ox.ac.uk/objects/uuid:2792e6e7-b1f9-4bd3-ad40-3dc96e113251

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