Coulomb stress changes and aftershocks of recent Indian earthquakes

Abstract

During the past decade remarkable progress has been made in studies related to fault interactions and how the occurrence of an earthquake perturbs the stress field in its neighbourhood, which may trigger aftershocks and subsequent earthquakes. These studies have significant implications on the seismic hazard assessment of a region, as the change in stress can cause either a delay or an advance in the occurrence of future earthquakes. Further, since the assessment of seismic hazard is dependent on the rupture parameters of past earthquakes, it is important to reliably estimate such parameters, viz. rupture location, geometry, and extent of past earthquakes. Here, we report the constraints on some of the rupture parameters of Indian earthquakes during the past 14 years, namely the 2001 Bhuj, 1999 Chamoli, 1997 Jabalpur, 1993 Killari and 1991 Uttarkashi earthquakes, which are derived using the available aftershock data and assuming that these aftershocks occurred in the zones of increased static stress. Analyses of teleseismic waveform of these earthquakes poorly constrained such parameters.