New 1D velocity model and absolute locations image the Mayotte seismic-volcanic region

Since May 2018, a major volcano-seismic crisis has been happening offshore Mayotte Island, in the Comoros archipelago. With 5.8 km3 of magma emitted from a deep reservoir, intense seismic activity and deformation that hasn’t stopped after more than 2 years, this crisis is unprecedented. Since May 2019, several oceanographic campaigns deployed a dense network of Ocean Bottom Seismometers (OBS), associated with previous and new land stations, around the new seismically active area. To place better constraints on the magmatic, hydrothermal and tectonic processes occurring in this area , we use the best located events from a dataset of more than 4000 manually-picked earthquakes to develop a new 1D velocity model for the area and to relocate all events. The new velocity model greatly improve earthquakes’ locations, with better RMS and ellipsoidal errors. The relocations with this new model show more constrained seismic structures for the previously identified clusters. The 1D model also provides better locations of the events without the OBS data, as used for the continuous daily monitoring, greatly improving the day-to-day hazard assessment for Mayotte population. Join Zoom Meeting https://us02web.zoom.us/j/84010101174?pwd=dHNyS0dCVHJhNzh0THROVmlESDZDUT09 Meeting ID: 840 1010 1174 Passcode: 712885