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- Title
Slow Slip as an Indicator of Fault Stress Criticality.
- Authors
Lambert, Valère
- Abstract
Fault regions inferred to be slowly slipping are interpreted to accommodate much of tectonic plate motion aseismically and potentially serve as barriers to earthquake rupture. Here, we build on prior work using simulations of earthquake sequences with enhanced dynamic fault weakening to show how fault regions that exhibit decades of steady creep or transient slow‐slip events can be driven to dynamically fail by incoming earthquake ruptures. Following substantial earthquake slip, such regions can be under‐stressed and locked for centuries prior to slowly slipping again. Our simulations illustrate that slow fault slip indicates that a region is sufficiently loaded to be failing about its quasi‐static strength. Hence, if a fault region is susceptible to failing dynamically, then observations of slow slip could serve as an indication that the region is critically stressed and ready to fail in a future earthquake, posing a qualitatively different interpretation of slow slip for seismic hazard. Plain Language Summary: Earthquakes are thought to predominantly occur along sections of faults that appear stuck and actively accumulating strain under tectonic plate motion. Other fault regions observed to be slowly slipping are thought to release some of this strain without causing strong shaking, potentially limiting the location and amount of fault slip in earthquakes. Here we present numerical simulations of long‐term fault slip that add to a body of work showing how fault areas can host different styles of slow slip for several decades prior to failing destructively when pushed by an incoming earthquake rupture. Our models show how relatively short‐term observations of slow fault slip compared to the recurrence of large earthquakes over several centuries can mask fault regions that are capable of experiencing substantial slip in future earthquakes. Importantly, our simulations suggest that if a fault region is capable of failing during an earthquake, then observations of slow slip may indicate that the region is favorably stressed to fail in a future earthquake, representing a qualitatively different interpretation of slow slip for seismic hazard. Key Points: Short‐term inferences of fault coupling provide limited insight into which faults regions can undergo large slip in future earthquakesSteady and transient slow slip indicates that fault stress levels are loaded near quasi‐static failure conditionsIf a fault region is susceptible to failing dynamically, slow slip may suggest it is critically stressed to fail in a future earthquake
- Subjects
SLOW earthquakes; EARTHQUAKES; PLATE tectonics; NATURAL disaster warning systems; FAULT location (Engineering); HAZARD mitigation
- Publication
Geophysical Research Letters, 2024, Vol 51, Issue 11, p1
- ISSN
0094-8276
- Publication type
Article
- DOI
10.1029/2023GL107356