Effect of regional tectonic setting on local fault response to episodes of volcanic activity

Abstract

In this study we examine the interaction of tectonic and volcanically-generated stress fields, and their combined effect on patterns of volcanotectonic (VT) seismicity, by calculating Coulomb stress changes on local faults induced by a constant dike inflation event in a background stress field of systematically varying magnitude and orientation. We find that patterns of VT seismicity (earthquake locations and fault-plane solutions) resulting from dike inflation depend strongly on the relative strength and orientation of background tectonic stresses. Patterns of VT seismicity similar to those predicted by our Coulomb stress models have been observed at several recently active volcanoes, and appear to correspond to the relative strength of the regional stress field. Thus, it is critical to consider the regional tectonic setting when interpreting patterns of VT seismicity in terms of magmatic processes. Copyright 2007 by the American Geophysical Union.