Séminaire ISTerre

Probing earthquake nucleation with machine learning

mardi 18 mai 2021 - 10h00

Claudia Hulbert - Ecole Normale Supérieure
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Active faults release tectonic stress imposed by plate motion through a spectrum of slip modes, from slow, aseismic slip, to dynamic, seismic events. Slow earthquakes are often associated with tectonic tremor, non-impulsive signals that can easily be buried in seismic noise and go undetected. We present new methodologies aimed at improving the automatic detection and location of tremor signals, in the laboratory and in Earth. We then rely on these approaches to probe the nucleation of earthquakes and slow slips. We show that patterns in seismic energy identified by machine learning point towards small and slow displacement preceding earthquake and slow slip rupture in the laboratory. Similar observations can be made preceding slow earthquakes in Cascadia: by analyzing over ten years of continuous seismic data, we find that slow slip failure is preceded by characteristic signals, small enough to not be captured in existing catalogs. Comparison with laboratory experiments suggests that these signals are generated by small-scale aseismic deformation, detectable over several months and leading up to the rupture. We then discuss early applications of our algorithms in different tectonic settings, with the goal of identifying potential aseismic deformation preceding large earthquakes.

Equipe organisatrice : Cycle sismique et déformations transitoires

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Sujet : Zoom meeting invitation - Seminar Claudia Hulbert
Heure : 18 mai 2021 10:00 AM Paris

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