Vertical Coseismic Offsets Derived From High‐Resolution Stereogrammetric DSM Differencing: The 2013 Baluchistan, Pakistan Earthquake

Abstract

The recent proliferation of high‐resolution (<3‐m spatial resolution) digital topography data sets opens a spectrum of geodetic applications in differential topography, including the quantification of coseismic vertical displacement fields. Most investigations of coseismic vertical displacements to date rely, in part, on preevent or postevent lidar surveys that are intractable or nonexistent in many locales. Stereogrammetric digital surface models (DSMs) derived from high‐resolution satellite optical imagery provide a new avenue for the retrieval of spatially dense vertical coseismic displacements on a global scale. In this study, we generated 2‐m resolution preseismic and postseismic DSMs from satellite optical imagery spanning the 2013 Mw7.7 Baluchistan strike‐slip earthquake that occurred on the Hoshab fault in southern Pakistan. We applied the Iterative Closest Point algorithm to the DSMs to quantify the coseismic vertical displacement field at a spatial resolution of 10–30 m and to generate 3‐D coseismic strain tensors. We found that across‐fault vertical offsets alternated between uplift and subsidence and varied between ~1 and 3 m in a nonsystematic manner along the Hoshab fault. We show that the preexisting topography and near‐fault geomorphology are variably consistent and inconsistent with the displacement kinematics of the 2013 earthquake, and we argue that these relationships highlight varied slip sense history along the Hoshab fault. Notably, topography along the southern extents of the Hoshab fault requires different surface displacement kinematics than occurred in the 2013 earthquake, suggesting that the Hoshab fault accommodates varying senses of slip (bimodal slip) through time.

Fault Geometry and Slip Distribution of the 2013 Mw 7.7 Balochistan Earthquake From Inversions of SAR and Optical Data

“…The horizontal solution we find is fully consistent with already published horizontal data (Avouac et al, 2014;Barnhart et al, 2015;Gold et al, 2015;Vallage et al, 2015;Zinke et al, 2014). We also measure up to 3 m of vertical motion across the fault (Figure 4b), showing evidence for reverse slip associated to this earthquake, as showed by Barnhart et al (2019). This motion induces an uplift of the NW block with respect to the SE block, consistent with a NW dipping fault with a thrust component.…”

Surface Rupture and Distributed Deformation Revealed by Optical Satellite Imagery: The Intraplate 2016 Mw6.0 Petermann Ranges Earthquake, Australia

“…While destriping tools, for example, within National Aeronautics and Space Administration's Ames Stereo Pipeline (Shean et al, ), are commonly applied to resolve this issue, a destriping correction has not been developed for this latitude. We used the Iterative Closest Point (ICP) algorithm to find the coseismic vertical displacement field from our preevent and postevent DEMs (Figure ; e.g., Barnhart et al, ; Besl & McKay, ; Nissen et al, ). ICP yields horizontal and displacement fields, and rotations by matching three‐dimensional features (topography) between DEMs.…”

“…• Data Set S1 A number of recent studies quantify vertical surface deformation associated with ground-rupturing earthquakes based on combinations of lidar, aerial photographs, satellite imagery, and InSAR data (Avouac & Leprince, 2015;Barnhart et al, 2019;Kuo et al, 2018;Nissen et al, 2014;Oskin et al, 2012;Scott et al, 2019;Zhou et al, 2018). This study contributes to this emerging field using high-resolution optical satellite imagery to measure vertical coseismic surface displacements produced by the 20 May 2016 M w 6.0 Petermann Ranges earthquake, Northern Territory, Australia.…”

Earth Observation for Crustal Tectonics and Earthquake Hazards

“…The baseline separation of images (often a couple of hundreds of kilometres apart) yields different perspectives of the Earth's surface from which a digital elevation model can be derived from using the process of photogrammetry (Noh and Howat 2015). Satellite systems that are able to acquire in-track panchromatic imagery at medium and high resolutions, and that have been applied to active tectonic faulting observations include the WorldView series (Barnhart et al 2019a), the pair of Satellite Pour l'Observation de la Terre (SPOT6/7) systems (Zhou et al 2016) and the two Pleiades satellites (Zhou et al 2015;Hodge et al 2019).…”