Seismic source displacement by coda wave interferometry at Soufrière Hills Volcano, Montserrat, WI

Abstract. Since the start of the ongoing eruption, on 18 July 1995, the Soufrière Hills Volcano (SHV) on Montserrat, WI, has been monitored with a network of seismometers providing an unparalleled wealth of observations. A recurrent and intriguing feature of the seismicity at SHV is the occurrence of regular swarms of low-frequency earthquakes during episodes of volcanic unrest. A notable example of this type of activity was recorded during the summer of 2008 when SHV erupted, on 29 July, following 15 days of seismic unrest. An impressive swarm of low-frequency earthquakes with strikingly similar waveforms, was recorded on 26 July through 27 July 2008. In this paper, the cross-correlation properties of the repeating earthquakes are investigated, and coda wave interferometry methods applied to infer seismic source displacement throughout the swarm.