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 volcano-tectonic earthquakes since August 2020, is located close to the Orca submarine volcano, previously considered inactive. Sim...
| Published in: | Communications Earth & Environment |
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| Main Authors: | , , , , , , , , , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | unknown |
| Published: |
2022
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| Subjects: | |
| Online Access: | https://gfzpublic.gfz-potsdam.de/pubman/item/item_5010958 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5010958_1/component/file_5011159/5010958.pdf |
| 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 volcano-tectonic 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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