ERC Starting Grant PRESEISMIC - The Nucleation of Earthquakes: Cascading and Unpredictable or Slowly driven and Forecastable
PROJECT SUMMARY The PRESEISMIC project addresses one of the key questions in seismology: how do earthquake begins? Much of what we know about earthquake nucleation comes from the observation of foreshock events before large earthquakes. Yet, a problem is the inherent difficulty to identify earthquakes as foreshocks before the mainshock occurs. Our understanding of earthquake nucleation is currently limited by (1) the difficulty to quantitatively estimate the proportion of seismic versus aseismic slip during rupture initiation and (2) the difficulty to detect and characterize small microearthquakes (with magnitude M<2), which are essential to assess if foreshocks are triggered by aseismic preslip. Both limitations clutter our understanding of the physical mechanisms controlling the relationship between foreshocks and the onset of large earthquakes. The overall objective of the PRESEISMIC project is to exploit near-fault observations to capture the genesis of earthquakes. In particular, we are developing new tools to distinguish random cascades of foreshocks from a behavior where earthquakes are driven by aseismic preslip. These approaches include time-dependent models to assimilate seismic and geodetic datasets and address the relative contribution of seismic and aseismic slip. We are also developing methods to improve seismicity catalogs and analyze earthquake interactions before a mainshock occurs. While such tools are useful to understand the initiation phase of earthquakes, they can calso be used in volcanic environments. We have therefore expanded our work on volcanoes to enable a better understanding of magma migration and improve the forecasting of volcanic eruptions. Current results are available in the Publications page. POSITIONS/OPPORTUNITIES People currently involved in the project are listed here. We always welcome applications from potential graduate students and postdocs. Topics include developments of new methods to monitor transient deformation signals, modeling of tectonic or volcanic deformation, study of large earthquakes, volcano seismicity, inverse methods, ... - PhD scholarship - Position filled (Lise Firode): We are hiring a PhD student who will develop new approach to improve seismicity catalogs. More details in the job announcement. - PhD scholarship - Position filled (Luc Moutote): We invite application for a highly motivated PhD candidate to investigate the initiation of large earthquakes using near-fault observations. More details in the job announcement. - Postdoctoral researcher - Position filled (C├ędric Twardzik): We are seeking a postdoc researcher to investigate the initiation of large earthquakes using near fault geodetic observations. More details in the job announcement.