Massive earthquake swarm driven by magmatic intrusion at the Bransfield Strait, Antarctica
An earthquake swarm affected the Bransfield Strait, Antarctica, a unique rift basin in transition from intra-arc rifting to ocean spreading. The swarm, counting ~85,000 volcanotectonic earthquakes since August 2020, is located close to the Orca submarine volcano, previously considered inactive. Simu...
Main Authors: | , , , , , , , , , , , , |
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Format: | Other Non-Article Part of Journal/Newspaper |
Language: | English |
Published: |
Springer Nature
2022
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Subjects: | |
Online Access: | https://elib.dlr.de/186138/ https://elib.dlr.de/186138/1/Cesca_etal_2022_s43247-022-00418-5.pdf https://www.nature.com/articles/s43247-022-00418-5 |
Summary: | An earthquake swarm affected the Bransfield Strait, Antarctica, a unique rift basin in transition from intra-arc rifting to ocean spreading. The swarm, counting ~85,000 volcanotectonic earthquakes since August 2020, is located close to the Orca submarine volcano, previously considered inactive. Simultaneously, geodetic data reported up to ~11 cm northwestward displacement over King George Island. We use a broad variety of geophysical data and methods to reveal the complex migration of seismicity, accompanying the intrusion of 0.26-0.56 km³ of magma. Strike-slip earthquakes mark the intrusion at depth, while shallower normal faulting the ~20 km long lateral growth of a dike. Seismicity abruptly decreased after a Mw 6.0 earthquake, suggesting the magmatic dike lost pressure with the slipping of a large fault. A seafloor eruption is likely, but not confirmed by sea surface temperature anomalies. The unrest documents episodic magmatic intrusion in the Bransfield Strait, providing unique insights into active continental rifting. |
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