Evidencing fluid migration of the crust during the earthquake cycle by using 1D-magnetotelluric monitoring

• Main Authors: Vargas Jimenez, C., Caneva, A., Solano, J., Gulisano, A., Villalobos, J.
• Format: Conference Object
• Language: English
• Published: 2023
• Subjects: Antarctic; Antarctic Peninsula; Bransfield Strait; King George Island; Marambio; Seymour; The Antarctic; Antarc*; Antarctica; Orca
• Online Access: https://gfzpublic.gfz-potsdam.de/pubman/item/item_5016453

We apply multi-temporal 1D-magnetotelluric (MT) surveys to identify space-time anomalies of apparent resistivity in the upper lithosphere in the Antarctic Peninsula (border between the Antarctic and the Shetland plates). We use time series over several weeks of the natural Earth's electric and magnetic fields registered at one MT station of the Universidad Nacional de Colombia (RSUNAL) located at Seymour – Marambio Island, Antarctica. We associate resistivity anomalies with contrasting earthquake activity. Anomalies of were detected almost simultaneously with the beginning of a seismic crisis in the Bransfield Strait, south of King George Island (approx. 85.000 events were reported close to the Orca submarine volcano, with focal depths < 20 km and m b < 6.9). We explain the origin of these anomalies in response to fluid migration near the place of the fractures linked with the seismic swarm, which could promote disturbances of the pore pressure field that reached some hundreds of km away.