An Inflating Upper Mantle Magma Reservoir Beneath the Tip of the Condor Seamount, Azores Revealed by Rapid‐Response Ocean‐Bottom‐Seismometer Data

Abstract

Condor Seamount is among the most seismically active regions on the Azores Plateau. In December 2019, an earthquake crisis occurred at the tip of the seamount, which was strongly felt on nearby islands. Two months after the peak of the crisis, we deployed a local network of five ocean‐bottom seismometers around the seamount, recording seismicity over 3 months. Using a machine‐learning‐based phase picker, we constructed a high‐resolution earthquake catalog. Jointly interpreting our local data and a long‐term regional catalog reveals episodic but spatially stable earthquake activity in the uppermost mantle. We propose the presence of an inflating magma reservoir that may feed a future eruption and extend the edifice westward. Furthermore, reversed P‐wave polarities were observed at the margin of the main earthquake swarm, but were absent in three other smaller swarms, supporting a local stress rotation model for magma intrusion.