Low frequency events occurred during the sequence of aftershock activity of the 2003 Tokachi-Oki earthquake; a dynamic process of the tectonic erosion by subducted seamount

Abstract

During the sequence of aftershock activity of the 2003 Tokachi-Oki earthquake, anomalous events predominant in low-frequency components occurred very close to a subducted seamount around the junction between the Kuril Trench and the Japan Trench. The low-frequency wave train in the coda part reflects the strong excitation of surface waves and the source depth is considered to be very shallow. The focal mechanism of the low-frequency event is a type of the reverse fault. Considering with the source depth and the mechanism, the low-frequency event might have occurred on the plate boundary as a dynamic process of the tectonic erosion by the subducted seamount.