Assessing the potential to detect vertical magma migration using seismicity through the analysis of the seismic network design

Abstract

Seismic swarms triggered by magma migration at volcanoes often imply an impending eruption. Using Seismic Amplitude Ratio Analysis (SARA) we have a tool to detect these migrations without having to do in-depth analysis of seismograms. This study examines the detection capability of SARA and introduces a new method to quantify it for different seismic network designs for different magma migrations. This is computed using the location of the seismic stations as well as a detection threshold defined using real swarm data. As an example, we applied the analysis to the Piton de la Fournaise seismic network and computed the volume under the volcano where the seismic network is capable to detect vertical migrations. Moreover, we evaluated the impact removing or adding seismic stations has on the detection capability of the network. This method provides a quick and straightforward way for volcano observatories to identify any detection gaps in a network, as well as providing a way to identify the type of migration event a network is most likely to detect.