| Abstrakt: |
Earthquake ruptures produce fault slip and kilometer‐wide diffuse deformation of the host rocks. However, the origin of the diffuse deformation and its role in the rupture process are debated. We produce a refined slip model for the 2019 Ridgecrest, California, earthquakes, and analyze the relations between down‐dip rupture process, and surface diffuse deformation. We show that the decrease in coseismic slip toward the ground surface, also known as shallow slip deficit (SSD), correlates with the occurrence of diffuse deformation at the surface, which is not accounted for by models assuming elastic host rocks. Hence, we suggest that a significant part of the SSD in earthquake source models could be interpreted as a proxy for shallow diffuse inelastic deformation around faults. Revisiting earthquake source models for 28 continental earthquakes, we discuss the controlling parameters of the SSD and diffuse deformation, and propose a conceptual model of the near‐field coseismic surface deformation. Plain Language Summary: Earthquakes can rupture up to the ground surface, generating displacements along faults and fractures that are visible in the field. This surface deformation can also be accompanied by diffuse deformation that occurs at a wider, >0.5 km, scale around the faults, and is imperceptible from a field perspective. Here, we use numerical modeling combined with detailed surface observations for the 2019 Ridgecrest, California, earthquakes to show that reduction in fault slip near the surface correlates with the occurrence diffuse deformation at the surface. Therefore, the reduction in shallow slip suggested in earthquake rupture models could be interpreted as a proxy for non‐elastic diffuse deformation around the faults. Compiling data for worldwide earthquake ruptures, we show that this process occurs similarly for other events, and we analyze the controlling parameters. Key Points: Refined slip model for the 2019 Ridgecrest earthquake sequence from the inversion of InSAR, optical, and GNSS dataShallow slip deficit is partially accounted for by diffuse deformation which likely involves bulk elastoplastic yieldingA compilation of published data on strike‐slip earthquakes highlights possible controlling parameters of the SSD and diffuse deformation [ABSTRACT FROM AUTHOR] |
Plný text