Vertical coseismic offsets from differential high-resolution stereogrammetric DSMs: The 2013 Baluchistan, Pakistan earthquake

Journal of Geophysical Research B: Solid Earth
By: , and 

Links

Abstract

The recent proliferation of high-resolution (< 3-m spatial resolution) digital topography datasets 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 pre- or post-event lidar surveys that are intractable or non-existent 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 pre- and post-seismic 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 3D coseismic strain tensors. We found that across-fault vertical offsets alternated between uplift and subsidence and varied between ~1-3 m in a non-systematic manner along the Hoshab fault. We show that the pre-existing 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.

Study Area

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Vertical coseismic offsets from differential high-resolution stereogrammetric DSMs: The 2013 Baluchistan, Pakistan earthquake
Series title Journal of Geophysical Research B: Solid Earth
DOI 10.1029/2018JB017107
Volume 124
Issue 6
Year Published 2019
Language English
Publisher American Geophysical Union
Contributing office(s) Geologic Hazards Science Center
Description 17 p.
First page 6039
Last page 6055
Country Pakistan
State Baluchistan Province