Water-level changes in the wells of Kamchatka at the time of the M w 7.6, April 20, 2006 Olyutorskii earthquake

摘要

The seismic waves excited by the M^sub ^sub w^^ 7.6 Olyutorskii earthquake that occurred on April 20, 2006 in the Koryak Upland gave rise to water-level changes in five wells situated in continental areas of Kamchatka at hypocentral distances of 750-1150 km. We describe the effects due to seismic waves, as well as the water-level anomalies for February-April 2006 before the earthquake. We used an original technique for the processing of water-level records based on the study of barometric and tidal water-level responses in order to estimate the volume strain in water-saturated rocks during synchronous level variations at two wells. We discuss possible mechanisms for producing anomalous water-level changes due to elastic deformation of monitored groundwater reservoirs and to crack dilatancy in the water-saturated rocks.[PUBLICATION ABSTRACT] Show less