Tectonic implications of earthquake mechanisms in Svalbard

Abstract

A new model for the local structure of the Svalbard archipelago, based on joint inversion of teleseismic receiver functions and regional surface wave dispersion, is optimized for waveform simulation at near-regional distances, thus allowing a better match between synthetic and observed waveforms for local earthquakes. We have used this model to calculate a moment tensor for the Mw 6.0 event of 2008 February 21 that occurred off Spitsbergen's southeast coast, and have reconciled the regional solution with the teleseismic solution. We have also compiled moment tensor solutions for other members of the earthquake sequence, which allow us to quantify the direction of maximum horizontal stress for the region. This direction does not align with the local direction of plate motion, and the difference between the two directions indicates the importance of local stress perturbations on the earthquake process near Svalbard. © The Authors 2013. Published by Oxford University Press on behalf of The Royal Astronomical Society.