Paleotsunamis from the central Kuril Islands segment of the Japan-Kuril-Kamchatka subduction zone

Abstract

AbstractPaleotsunami records from the central Kuril Island segment of the Japan-Kuril-Kamchatka subduction zone indicate that the region has been frequently inundated by tsunamis. As many as 20e22 tsunami deposits are recognized on Matua Island for the past 3300 yr with an average tsunami recurrence interval of ~150 yr, and 34e36 tsunami deposits are evident on Simushir Island for the past 2350 yr with an average recurrence of ~65 yr. These intervals are short, but comparable to other segments of the Japan-Kuril-Kamchatka subduction zone. Results from all survey locations reveal shortening recurrence intervals toward the present, especially for the last 600 yr, indicating a possible preservation bias. On Simushir, tsunamis at least 11 m higher than the modern tsunamis in 2006 and 2007 occurred every ~300 yr on average. On Matua, tsunamis with slightly farther inundation than the 2006 and 2007 tsunamis occurred every ~215 yr while those with at least 100 m farther inland inundation occur every ~750 yr. Our paleotsunami record almost certainly includes tsunamis that are not from great subduction zone earthquakes in the central Kuril segment: we expect the Matua record includes volcanic tsunamis and the Simushir record includes tsunamis from the southern Kuril segment.