Influence of crustal lithology and the thermal state on microseismicity in the Wakayama region, southern Honshu, Japan

Abstract Here we investigate the influence of lithology and thermal state upper crust on earthquake distributions beneath Wakayama region, southern Honshu, Japan, to better understand crustal conditions regional seismogenesis. The earthquakes are concentrated in deeper sections mafic belts shallower pelitic belts, based a comparison relocated hypocenters estimated subsurface geological structures. We compare frictional properties rocks basalt, as obtained from petrological experiments, with hypocenter depth assess control extent seismicity. consistent temperature ranges over which respective rock types expected exhibit velocity-weakening behavior, experiments. results suggest that occurrence shallow intraplate is controlled by temperature- lithology-dependent friction crust.