| Abstrakt: |
The thickness of a seismic slip layer controls style and rate of rupture propagation, frictional heating, weakening, and energy budget of earthquakes. Slip layer thickness changes dynamically with feedbacks between temperature rise, roughness, damage, and fluid pressurization. Natural faults have complex slip histories, ambiguating which layer thicknesses represent a record of seismic slip. The thickness of proven paleoseismic slip layers in nature are ∼ ${\sim} $1 mm–1 cm. Thicker slip layers do not get hot enough to retain coseismic frictional temperature anomalies and thereby prevent the detection of big earthquakes using current methods. We suggest that delocalization—the spontaneous increase in slipping layer thickness during slip—plays a role in coseismic healing and cause biases in the rock record of earthquakes. Recognizing the importance of feedbacks affecting slipping layer thickness is critical to understanding strength and stress variations during earthquakes and to correctly interpreting earthquake source parameters from exhumed faults. Plain Language Summary: Faults get hot during earthquakes, and hot faults are weaker. The temperature depends on the thickness of the rock layer which slips in the earthquake. We developed criteria for identifying the slip layer from a single earthquake and compiled the measured thicknesses, finding that these slip layers are typically about 1 mm–1 cm thick regardless of the type of fault and the depth of faulting. We show that this thickness represents a balance between frictional heat production and dissipation. In nature, and sometimes in the lab, the slip layers can broaden during slip (delocalize) which could limit the size of earthquakes. Key Points: Seismic slip layers are ∼1 mm−1 cm thick, regardless of temperature, rock type, or depth, balancing heat production and dissipationThicker earthquake slip layers are possible but cannot be detected by current methodsCo‐seismic delocalization may strengthen faults and limit total slip in earthquakes [ABSTRACT FROM AUTHOR] |
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