Stacking of distributed dynamic strain reveals link between seismic
velocity changes and the 2020 unrest in Reykjanes
Abstract
In this study, we measure velocity variations during two cycles of
crustal inflation and deflation in 2020 on the Reykjanes peninsula (SW
Iceland) by applying coda wave interferometry to ambient noise recorded
by distributed dynamic strain sensing (also called DAS). We present a
new workflow based on spatial stacking of raw data prior to
cross-correlation which substantially improves the spatial coherency and
the time resolution of measurements. Using this approach, a strong
correlation between velocity changes and ground deformation (in the
vertical and horizontal direction) is revealed. Our findings may be
related to the infiltration of volcanic fluids at shallow depths, even
though the concurrent presence of various processes complicates the
reliable attribution of observations to specific geological phenomena.
Our work demonstrates how the spatial resolution of DAS can be exploited
to enhance existing methodologies and overcome limitations inherent in
conventional seismological datasets.