Seismotectonics of the Lesser Antilles Arc

Background:
Subduction zones are the sites of the world's largest earthquakes, sometimes generating devastating tsunamis. The earthquake potential of the Lesser Antilles Arc (LAA) is poorly known, largely because of the challenge of obtaining data along this arc of small islands. Two historic earthquakes are thought to have been classical subduction thrust events, possibly with tsunamigenic potential. However, the extent of megathrust seismic coupling remains debated. The
potential risk to large, poorly-protected communities in the Caribbean region is large.
Rationale:
In a recent large consortium grant, VoiLA, we collected new seismic data, including seabed-installed instruments, in and around the LAA. Data from our experiment has been used to image the subduction zone in unprecedented detail. We have compiled a preliminary catalogue of earthquakes detected during our deployment and developed a new moment tensor method to characterise faulting styles. We have been able to track how regions of more extensively hydrated
incoming plate correlate with concentrations of small earthquakes and enhanced volcanic productivity along the arc. The next stage is to undertake an in-depth analysis of the VoiLA data to improve understanding of earthquake potential of the LAA.
This project:
In this PhD project the VoiLA seismic data will be used together with thermal and mechanical odels of the subduction zone to improve the understanding of the seismic potential and tectonics of the LAA. Machine learning techniques will be used to identify and locate as many events as possible, to characterise the spatial distribution, size-frequency characteristics and where possible styles of events. These results will be combined with existing earthquake catalogues, and then
compared with predictions of the thermal structure and subducting plate stresses from models that are tailored based on our detailed imaging of the subduction zone. Given the LAA is an important end-member, where slow-convergence of The student would join the Imperial Plates, Mantle and Core group working on shallow and deep geophysical imaging, surface processes and mantle dynamics.