A Comprehensive Catalog of Repeating Earthquakes for Northern California: Implications for Fault Creep, Slip Rates, Slip Partitioning and Transient Stress
Repeating earthquakes, earthquakes that rupture the same fault patch more than once, are playing an important role in the study of source processes and fault behavior and have the potential to improve hazard assessment and earthquake forecast. They are believed to represent brittle failure of a stuck patch (asperity) on an otherwise creeping fault, and as such may offer insight into slip behavior at depth. We present a new catalog of repeating earthquakes for northern California developed by a systematic analysis of the entire NCSN waveform archive between 1984 and 2014 to identify earthquakes that are co-located, are of similar size and share similar waveforms. We find 27,675 events in 7,713 repeating earthquake sequences (RES) that include between 2 and 32 events with magnitudes between -0.5 and 6.5. Temporal behavior of the events within each RES ranges between random and quasi-periodic over the 30-year observation period and includes temporal clustering (bursts). The RESs occur throughout northern California, with some of the largest and most periodic sequences predominately, but not exclusively, along faults within the San Andreas Fault system that exhibit surface creep. Piecewise periodic RESs are found near large earthquakes where they are modulated by transient stress. Slip rates inferred from the new data, while generally consistent with published estimates from geodetic and surface data, offer a high-resolution image of subsurface creep along individual fault strands and resolve slip partitioning across wider zones of deformation. The new repeater catalog forms the baseline for routine detection and analysis of repeating events in real-time to help monitor changes in fault properties and loading rates.
Session: Searching for Fault Creep Over a Range of Timescales [Poster]
Type: Poster
Room: Evergreen Ballroom
Date: 4/20/2022
Presentation Time: 08:00 AM Pacific
Presenting Author: Felix Waldhauser
Student Presenter: No
Additional Authors
Felix Waldhauser Presenting Author Corresponding Author felixw@ldeo.columbia.edu Lamont-Doherty Earth Observatory, Columbia University |
David Schaff dschaff@ldeo.columbia.edu Lamont-Doherty Earth Observatory, Columbia University |
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A Comprehensive Catalog of Repeating Earthquakes for Northern California: Implications for Fault Creep, Slip Rates, Slip Partitioning and Transient Stress
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