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Tracking a Precursory Phase: The Case of the Mw 6.3 2009 L’aquila Earthquake

Session: New Insights Into the Preparatory Phase of Earthquakes From Tectonic, Field and Lab Experiments I

Type: Oral

Date: 4/19/2021

Presentation Time: 10:15 AM Pacific

Description: 

Whether the precursory seismicity sequences can alert us about an upcoming earthquake is one of the biggest challenges and open questions in seismology. On April 6^th 2009, the Mw 6.3 L’Aquila earthquake struck central Italy causing damage and fatalities, and was preceded by an intense foreshocks sequence. We create a high-resolution catalog using template matching to study the temporal evolution of the physical parameters and processes that played a role in the precursory phase of this earthquake. We thus track occurrence statistics, seismic moment release, effective stress drop and spatial evolution of the foreshock sequence. The spatio-temporal evolution of these parameters reveals how the sequence started as a swarm-type seismicity and evolved into mainshock-aftershock behavior. Our results suggest a complex precursory phase with interaction of several physical processes (diffusive fluid migration process, slow slip event and/or stress transfer). Our work highlights how a dense near-fault catalog can shed new light on the complex nucleation processes prior to major earthquakes.

Presenting Author: Leoncio Cabrera

Student Presenter: Yes

Authors