Séminaire ISTerre

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The legacy of MEDUSA: Tracking subduction fluids and earthquakes deep beneath western Greece

lundi 30 mai 2022 - 15h00

Stéphane Rondenay - University of Bergen, Norway
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Abstract: What causes instraslab earthquakes in subduction zones? The Hellenic subduction system provides a natural laboratory for exploring this question owing to its complex structure straddling two subduction regimes. I will discuss key results from data collected across western Greece, primarily from the MEDUSA dense teleseismic array. This work has provided important new insight both into the subduction dynamics of the Western Hellenic Subduction Zone and into fluid processes operating in subduction zones globally. High-resolution seismic images show that subduction in western Greece transitions from rapidly retreating oceanic slab subduction in the south to slow-converging continental slab subduction in the north. Intraslab seismicity stops exactly at the transition from oceanic to continental subduction, pointing to fluids as playing a key role in the generation of these earthquakes. Closer inspection of the earthquakes reveals the existence of localized seismicity clusters at the plate interface and in the mantle wedge. These patterns of seismicity, also detected in other subduction zones worldwide, suggest that earthquakes in cold subduction zones track the migration of fluids from their source in the slab to their sink in the mantle wedge.

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Equipe organisatrice : Cycle sismique et déformations transitoires

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères

Informations de visio :

Sujet : Zoom meeting invitation - Seminar Stéphane Rondenay
Heure : 30 mai 2022 03:00 PM Paris

Participer à la réunion Zoom
https://univ-grenoble-alpes-fr.zoom.us/j/93078506502?pwd=Wk1UODJsUURPd0JnZStWZWhnbXNUdz09

ID de réunion : 930 7850 6502
Code secret : 159907