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The Rise and Fall of Earthquake-Size Distribution With Depth: Insights From the Calabrian Subduction Zone

Description: 

The magnitude distribution of earthquakes is generally represented by an exponential function controlled by one parameter, called the b-value. This parameter is related to different characteristics of the earthquakes, like the faulting mechanism, and the earth's crust, like the differential stress. Maps of the b-value have shown anomalies of high values associated with the depth of a number of subduction zones. Here, we investigated the possible dependence of the b-value with the subduction depth for intra-slab earthquakes by using a homogeneous instrumental seismic catalog and a high-definition model of the Calabrian Slab, which represents one of the oldest oceanic crust in the world presently subducting. We found a rise of the b-value until a depth of about 150 km, and then a fall from 150 to 300 km. This peculiar behavior is interpreted in relation to dehydration and partial melting of the subducting slab. Our results are important for characterizing the behavior of a subducting slab and for seismic hazard analysis, since they help to understand the earthquake size distribution of a subduction zone, usually the most seismogenic zones of the Earth. With a better spatial and depth resolution of the b-value variation it is possible to improve the modeled seismic hazard.

Session: Opportunities and Challenges in Source Modeling for Seismic Hazard Analysis [Poster]

Type: Poster

Date: 4/20/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: Matteo Taroni

Student Presenter: No

Invited Presentation: 

Authors