Seismic Tomography of a Newborn Volcano

On 19 September 2021, in La Palma, Canary Islands (Spain), a new volcano, later named Tajogaite, erupted. We determined the shallow seismic tomography model of Tajogaite Volcano, including the 3D distributions of Vp, Vs, and Vp/Vs. The tomography of the volcanic edifice has been performed using a combination of a three-component amplitude method for seismic event detection and a sophisticated deep neural network method for picking first arrival times, which allowed the detection and the picking of thousands of earthquakes from a data set recorded by a temporary network deployed around the main crater just a few months after the end of the eruption. We identified shallow low Vp/Vs and deeper high Vp/Vs anomalies, which we interpret as changes in the fluid filling the rocks, transitioning from liquid to steam at shallower low-pressure conditions. Our work highlights, for the first time, the internal structure of a monogenetic volcano, specifically its evolving local hydrothermal system, right after its eruption.