[S-CG45] Science of slow-to-fast earthquakes

[SCG45-18] Factors producing asynchronous fluid flow and slip behavior in subduction zones

*John Noel Hooker¹、Donald M Fisher² (1.University of the Incarnate Word、2.The Pennsylvania State University)

キーワード：Earthquake, Subduction zone, Fluid flow, Structural diagenesis, Fault healing

Geochemical data from rocks deformed along the subduction interface produce some of the most important insights into co- and interseismic fluid fluxes. These fluxes in turn influence the seismic cycle through their effects on fault healing and effective stress. However, high-temporal-resolution data are difficult to collect, especially in the rock record, and the dynamics between seismicity and fluid pressures are therefore difficult to constrain. These difficulties limit our ability to answer basic questions concerning causes and effects between fluid fluxes and slip events. Here we present a numerical modeling study that integrates fluid flow, healing, and earthquake slip to study the synchronicity, or lack thereof, between fluid flow events and seismic ruptures. We find that fluid pressure on the plate interface can vary from closely coupled with slip events to nearly completely uncoupled, depending on the permeability of healed and unhealed portions of the interface, as well as on the rate of fluid introduction. These results suggest a rich variety of behaviors are possible in natural fault zones, especially when the effects of spatial variations in permeability, structure, and lithology are considered. Continued field research in modern and ancient settings will further elucidate the complexities of natural fault zone processes.