Co-seismic stress changes and triggering mechanism of earthquake-induced landslides: a case of 2005 Kashmir earthquake

Abstract

Kashmir earthquake of October 8, 2005, was the most devastating in the recent history of South Asia, causing more than 86,000 casualties, and was accompanied by numerous slope failures. Like many other earthquakes hitting the rugged mountainous terrains of developing countries, strong ground motion records of Kashmir earthquake were also deficient. In the absence of waveforms, source inversion analysis of the geodetic data is performed to reveal spatial distribution of slip on a 90 km\u2009×\u200930 km fault rupture plan with dip and strike angles of 29° and 320°, respectively. The largest asperity, having a maximum slip value of 7.5 m, has appeared at the same location where the large crustal deformation was detected. The slip distribution pattern near the ground surface is consistent with the crustal deformations. Also, seismic stresses are calculated for the epicentral areas for a stratified half-space through forward modeling. All the landslides triggered by Kashmir earthquake are spotted in the areas having high values of square root of the second principal invariant of deviatoric stress tensor (J2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sqrt{{J}_{2}}$$\\end{document}), witnessing a relationship between co-seismic stresses and earthquake-induced landslides. This study will be helpful to rationally understand earthquake-induced damages, their scientific basis, and to establish a cause-and-effect relation between the seismic activity and damaged pattern which can be helpful for rehabilitation, disaster management, and preparedness for future seismic disasters.