Details

Autor(en) / Beteiligte

• Kawakami, Gentaro
• Kase, Yoshihiro
• Urabe, Atsushi
• Takashimizu, Yasuhiro
• Nishina, Kenji

Titel

Tsunamis and possible tsunamigenic deposits along the eastern margin of the Japan Sea

Ist Teil von

• Chishitsugaku zasshi, 2017-10, Vol.123 (10), p.857-877, Article 2017.0054

Ort / Verlag

Tokyo: Japan Science and Technology Agency

Erscheinungsjahr

2017

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Extensive research has been conducted on tsunamigenic deposits along the eastern margin of the Japan Sea since the 2011 Tohoku Earthquake and tsunami. This paper reviews the characteristics of the large known tsunamis and the possible tsunamigenic deposits identified in this region. We have also reconstructed the spatio-temporal distribution, and a provisional correlation, of the tsunamigenic deposits in order to estimate the tsunami recurrence intervals and their wave source regions. Most of the tsunamigenic deposits were recognized in peaty and marshy deposits found on swales of coastal dunes, flood plains, and small valley plains. Large numbers of tsunamigenic sandy layers were also identified in lagoonal deposits. In addition, some gravelly deposits of possible tsunamigenic were recognized on top of low-lying marine terraces and slope talus. Although several historical tsunamis in the 18-19th centuries have been recorded along the eastern margin of the Japan Sea, there are few localities where deposits can be correlated to these records. Tsunamigenic deposits suggest that four tsunami events have occurred during the 9-14th centuries, despite there being limited historical records of tsunamis older than the 18th century. The distribution of these four deposits is as follows: 14th century = Aomori-northern Yamagata; 12th century = southwestern Hokkaido; 11th century (?1092 AD) = Sado/Niigata-southern Yamagata; 9th century (?850 AD) = (Sado)-Yamagata-Aomori. These events are also recorded in the deep-sea Japan Basin as seismo-turbidites. Most tsunamigenic deposits older than the 9th century have only been identified at remote islands (Okushiri, Tobishima, and Sado). Several unanswered research questions on these tsunamigenic deposits remain, such as robust identification of the origins and precise ages of the deposits. Our work provides a framework for future screening of potential tsunamigenic deposit data and an improved understanding of paleotsunami events along the eastern margin of the Japan Sea.