Rupture Process of the 2020 Caribbean Earthquake Along the Oriente Transform Fault, Involving Supershear Rupture and Geometric Complexity of Fault
Abstract
A large strike‐slip earthquake occurred in the Caribbean Sea on January 28, 2020. We inverted teleseismic P waveforms from the earthquake to construct a finite‐fault model by a new method of inversion that simultaneously resolves the spatiotemporal evolution of fault geometry and slip. The model showed almost‐unilateral rupture propagation westward from the epicenter along a 300 km section of the Oriente transform fault with two episodes of rupture at speeds exceeding the local shear‐wave velocity. Our modeling indicated that the 2020 Caribbean earthquake rupture encountered a bend in the fault system associated with a bathymetric feature near the source region. The geometric complexity of the fault system triggered multiple rupture episodes and a complex rupture evolution. Our analysis of the earthquake revealed complexity of rupture process and fault geometry previously unrecognized for an oceanic transform fault that was thought to be part of a simple linear transform fault system.
Plain Language Summary
On 28 January 2020, a large earthquake occurred on the Oriente fault, an oceanic transform fault in the Caribbean Sea between Jamaica and Cuba. The Oriente fault forms the boundary between the North America and Caribbean tectonic plates. The 2020 Caribbean earthquake was caused by horizontal sliding between the two plates. We used waveforms of the earthquake that were recorded around the world to build a model of the earthquake‐rupture process. The model showed that rupture during the earthquake was complex, featuring multiple rupture episodes with various rupture speeds and in various directions. Our model suggests that a bend in the fault was responsible for the changes of rupture speed and direction and the triggering of successive rupture episodes. Our analysis of the 2020 Caribbean earthquake has revealed complexity of both fault geometry and rupture process that were previously unknown in oceanic transform fault earthquakes.
Open Research
Data Availability Statement
Teleseismic waveforms were obtained from the following networks: GEOSCPPE (G; https://doi.org/10.18715/GEOSCOPE.G); the Global Seismograph Network (GSN IRIS/IDA, II; https://doi.org/10.7914/SN/II); the Global Seismograph Network (GSN IRIS/USGS, IU; https://doi.org/10.7914/SN/IU); the Canadian National Seismograph Network (CN; https://doi.org/10.7914/SN/CN); the Czech Regional Seismic Network (CZ; https://doi.org/10.7914/SN/CZ); the Netherlands Seismic and Acoustic Network (NL; https://doi.org/10.21944/e970fd34-23b9-3411-b366-e4f72877d2c5); the Mediterranean Very Broadband Seismographic Network (MN; https://doi.org/10.13127/SD/fBBBtDtd6q); the Global Telemetered Seismograph Network (GTSN USAF/USGS, GT; https://doi.org/10.7914/SN/GT); the Southern California Seismic Network (CI; https://doi.org/10.7914/SN/CI); and the Berkeley Digital Seismograph Network (BK; https://doi.org/10.7932/BDSN). The moment tensor solutions are obtained from the GCMT catalog (https://www.globalcmt.org/CMTsearch.html). The Tsunami height is available by the NOAA (https://www.tsunami.gov). The CRSUT 1.0 and CRUST 2.0 structural velocity models are available through the websites (https://igppweb.ucsd.edu/~gabi/crust1.html) and (https://igppweb.ucsd.edu/∼gabi/crust2.html), respectively.
