ASEISMIC: Detecting and characterizing episodic aseismic forcing – ASEISMIC

Goal: To detect, characterize, and model aseismic, earthquake-triggering events (silent earthquakes, afterslip, fluid pulses and intrusions) by studying how they affect earthquake occurrence rates. Episodic, aseismic forcing can cause transient increases of seismicity, like for example earthquake swarms. The aseismic source is generally not well resolved, if at all, except in rare occasions where surface deformation can be monitored with sufficiently high precision. We are therefore generally left guessing what the source is, based solely on its seismicity fingerprint. There are two equally important aspects in this problem: (1) we need to have accurate and robust probabilistic methods for detecting and characterizing aseismic sources that could potentially drive local seismicity transients; (2) we should try to a priori constrain the source characteristics by forward modelling how a given aseismic event can trigger earthquakes, depending on its spatial extent, duration, and intensity (total slip or pressure change). We will study these two closely related aspects. To do so, a team of 6 scientists (from LGIT in Grenoble and Chambéry, and IPG in Paris, 4 of which are young scientists) will collaborate, with the aim of building a complementary and long-lasting team effort to study earthquake triggering mechanisms in the broad context where both seismic and aseismic deformation sources are equally considered.