1. Rare Occurrences of Non‐cascading Foreshock Activity in Southern California
- Author
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Moutote, L., Marsan, D., Lengliné, O., Duputel, Z., Institut Terre Environnement Strasbourg (ITES), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre (ISTerre), and Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Gustave Eiffel-Université Grenoble Alpes (UGA)
- Subjects
Informatics ,foreshock ,Sequence model ,010504 meteorology & atmospheric sciences ,Earthquake Source Observations ,010502 geochemistry & geophysics ,01 natural sciences ,mainshock nucleation ,Ionospheric Physics ,ETAS ,ComputingMilieux_MISCELLANEOUS ,Seismology ,Earthquake Interaction, Forecasting, and Prediction ,Aftershock ,cascade of earthquakes ,Exploration Geophysics ,Gravity Methods ,Ocean Predictability and Prediction ,Anomaly (natural sciences) ,Seismic Cycle Related Deformations ,Tectonic Deformation ,Oceanography: General ,Policy ,Geophysics ,Time Variable Gravity ,Estimation and Forecasting ,Seismicity and Tectonics ,Space Weather ,Mathematical Geophysics ,Probabilistic Forecasting ,Geology ,Temporal clustering ,[PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] ,Satellite Geodesy: Results ,Induced seismicity ,Southern California ,Radio Science ,Earthquake detection ,Earthquake Dynamics ,[SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology ,Research Letter ,Magnetospheric Physics ,Geodesy and Gravity ,Ionosphere ,Monitoring, Forecasting, Prediction ,Solid Earth ,0105 earth and related environmental sciences ,[SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics ,Gravity anomalies and Earth structure ,Continental Crust ,low completeness catalog ,Policy Sciences ,Foreshock ,Earthquake catalog ,Interferometry ,13. Climate action ,General Earth and Planetary Sciences ,Subduction Zones ,Hydrology ,Transient Deformation ,Prediction ,Natural Hazards ,Forecasting - Abstract
Earthquakes preceding large events are commonly referred to as foreshocks. They are often considered as precursory phenomena reflecting the nucleation process of the main rupture. Such foreshock sequences may also be explained by cascades of triggered events. Recent advances in earthquake detection motivates a reevaluation of seismicity variations prior to mainshocks. Based on a highly complete earthquake catalog, previous studies suggested that mainshocks in Southern California are often preceded by anomalously elevated seismicity. In this study, we test the same catalog against the Epidemic Type Aftershock Sequence model that accounts for temporal clustering due to earthquake interactions. We find that 10/53 mainshocks are preceded by a significantly elevated seismic activity compared with our model. This shows that anomalous foreshock activity is relatively uncommon when tested against a model of earthquake interactions. Accounting for the recurrence of anomalies over time, only 3/10 mainshocks present a mainshock‐specific anomaly with a high predictive power., Key Points We further investigate previous claims of significantly elevated seismic activity prior to large earthquakes in Southern California10 out of 53 mainshocks are preceded by anomalously high seismicity, but only 3 of these anomalies are exclusively related to the mainshockThese selected foreshock sequences are likely due to additional pre‐slip, aseismic processes
- Published
- 2021
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