Illuminating mantle structures at Western Galápagos using seismic interferometry by autocorrelation with body waves

Abstract

The Galápagos archipelago is one of the regions with the highest rates of eruption and surface magma emissionin the world. Knowledge about the subsurface structure is fundamental for a better understanding of thedynamics of the magmatic systems in the area. However, the details of the internal architecture beneath thearchipelago remain poorly constrained at both shallow and deep levels. To shed light on these, we applyseismic interferometry by autocorrelation to records of earthquakes with epicentral distances greater than 30◦,obtained from 18 broadband stations deployed around two volcanoes (Cerro Azul and Sierra Negra) located inWestern Galápagos, which is characterized by the highest volcanic activity of the archipelago. The methodologywe apply results in the identification of the main mantle discontinuities at a wide range of depths with highresolution. We combine the individual results from all stations to construct a representative depth model forthe entire region down to a depth of 800 km. Our results reveal coherent reflectivity patterns consistent withpreviously identified mantle structures and define the extent and location of the Galápagos mantle plume.These findings provide new insights into the mantle structure beneath the archipelago and can be used toimprove our understanding of plume processes driving volcanism and its surface expression in the region.