Although moderate-size earthquakes are poorly studied by lack of near-fault observations, they can provide key information about larger damaging earthquakes. Here we propose a new approach, inspired by double-difference relocation, that uses high-coherency waveforms recorded at neighboring sensors, to study the preparation phase and dynamics of moderate-size earthquakes. We validate this technique by analyzing the 2016, 5.2 Borrego Springs earthquake in Southern California and find consistent rupture velocities of 2 km/s highlighting two main rupture asperities. The analysis of the 2019, l5.2 Le Teil earthquake in France reveals slow nucleation at depth that migrates to the surface and propagates northward with a velocity of ∼2.8 km/s, highlighting two main rupture events also imaged by InSAR. By providing unprecedented resolution in our observation of the rupture dynamics, this approach will be useful in better understanding the preparation phase and rupture of both tectonic and induced earthquakes.
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http://dx.doi.org/10.1029/2020GL088563 | DOI Listing |
Heliyon
May 2024
Federal University of Rio Grande do Norte, Departament of Geophysics, Natal, RN, 59078-970, Brazil.
Stable continental regions pose unique challenges for conducting Probabilistic Seismic Hazard Analysis because the earthquake activity driving mechanisms are poorly understood. For instance, the lower seismicity (hence the paucity of data) and the absence of well-defined active fault systems complicate accurately determining seismic source parameters. Northeastern Brazil is a stable continental region exhibiting moderate-size events recorded with significant seismic intensities and provoking the collapse of poorly constructed buildings in the last century.
View Article and Find Full Text PDFNature
April 2021
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA.
The largest effusive basaltic eruptions are associated with caldera collapse and are manifest through quasi-periodic ground displacements and moderate-size earthquakes, but the mechanism that governs their dynamics remains unclear. Here we provide a physical model that explains these processes, which accounts for both the quasi-periodic stick-slip collapse of the caldera roof and the long-term eruptive behaviour of the volcano. We show that it is the caldera collapse itself that sustains large effusive eruptions, and that triggering caldera collapse requires topography-generated pressures.
View Article and Find Full Text PDFGeophys Res Lett
September 2020
Université Côte d'Azur, IRD, Observatoire de la Côte d'Azur, CNRS, Géoazur Valbonne France.
Although moderate-size earthquakes are poorly studied by lack of near-fault observations, they can provide key information about larger damaging earthquakes. Here we propose a new approach, inspired by double-difference relocation, that uses high-coherency waveforms recorded at neighboring sensors, to study the preparation phase and dynamics of moderate-size earthquakes. We validate this technique by analyzing the 2016, 5.
View Article and Find Full Text PDFRisk Anal
October 2019
Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, CO, USA.
Probabilistic risk assessment (PRA) is a useful tool to assess complex interconnected systems. This article leverages the capabilities of PRA tools developed for industrial and nuclear risk analysis in community resilience evaluations by modeling the food security of a community in terms of its built environment as an integrated system. To this end, we model the performance of Gilroy, CA, a moderate-size town, with regard to disruptions in its food supply caused by a severe earthquake.
View Article and Find Full Text PDFSci Rep
September 2018
Gyeongsang National University, Department of Earth and Environmental Sciences and RINS, Jinju, Gyeongsangnam-do, 660-701, South Korea.
The distance-dependent coseismic and postseismic displacements produced by the 2011 M9.0 Tohoku-Oki megathrust earthquake caused medium weakening and stress perturbation in the crust around the Korean Peninsula, increasing the seismicity with successive M5-level earthquakes at the outskirts of high seismicity regions. The average M5-level occurrence rate prior to the megathrust earthquake was 0.
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