Thermal squeezing of the seismogenic zone controlled rupture of the volcano-rooted Flores Thrust.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 33514553.
- Also identified by DOI 10.1126/sciadv.abe2348 and PMC identifier 7846177.
- Licence recorded as CC BY-NC.
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Abstract
Temperature plays a critical role in defining the seismogenic zone, the area of the crust where earthquakes most commonly occur; however, thermal controls on fault ruptures are rarely observed directly. We used a rapidly deployed seismic array to monitor an unusual earthquake cascade in 2018 at Lombok, Indonesia, during which two magnitude 6.9 earthquakes with surprisingly different rupture characteristics nucleated beneath an active arc volcano. The thermal imprint of the volcano on the fault elevated the base of the seismogenic zone beneath the volcanic edifice by 8 km, while also reducing its width. This thermal "squeezing" directly controlled the location, directivity, dynamics, and magnitude of the earthquake cascade. Earthquake segmentation due to thermal structure can occur where strong temperature gradients exist on a fault.