Tsunamis and submarine landslides in Suruga Bay, central Japan, caused by Nankai-Suruga Trough megathrust earthquakes during the last 5000 years

QUATERNARY SCIENCE REVIEWS

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Article

Kitamura, Akihisa^1,2  Yamada, Kazuyoshi³  Sugawara, Daisuke⁴  Yokoyama, Yusuke⁵  Miyairi, Yosuke⁵ 

[1] Shizuoka Univ, Fac Sci, Suruga Ku, 836 Ohya, Shizuoka 4228529, Japan

[2] Shizuoka Univ, Ctr Integrated Res & Educ Nat Hazards, Suruga Ku, 836 Ohya, Shizuoka 4228529, Japan

[3] Waseda Univ, Dept Human Behav & Environm Sci, Sch Human Sci, 2-579-15 Mikajima, Tokorozawa, Saitama 3591192, Japan

[4] Tohoku Univ, Int Res Inst Disaster Sci, Aoba Ku, E303 468-1 Aoba, Sendai, Miyagi 9808572, Japan

[5] Univ Tokyo, Atmosphere & Ocean Res Inst, 5-1-5 Kashiwanoha, Kashiwa, Chiba 2778564, Japan

关键词: Tsunami deposits;    Submarine landslides;    Nankai-suruga megathrust earthquakes;    Middle-late Holocene;   

DOI  :  10.1016/j.quascirev.2020.106527

来源: Elsevier

【 摘 要 】

Magnitude 8 megathrust earthquakes that have generated large tsunamis with wave heights of >5 m in coastal areas of southwestern Japan have occurred every 100-150 years along the Nankai-Suruga Trough, which marks the convergent boundary between the Eurasian and Philippine Sea plates. Using sedimentological, geochemical, and paleontological analyses, as well as C-14 dating, we examined tsunami deposits in 12 sediment cores collected from the Hamatome lowland, Yaizu Plain, Shizuoka, which faces the Suruga Trough. Four sandy tsunami deposits (Sands 1-4) are identified in sediments deposited during the last 5000 years. Sand 1 was deposited between 805 and 405 BC, suggesting that only one tsunami left a sedimentological imprint in the Hamatome lowland lagoon during the period of similar to 4000 years between 3090 and 2913 BC and the AD 1096 Eicho-Tokai earthquake. This very low frequency of tsunami inundation may suggest that this tsunami was larger than those typically associated with megathrust earthquakes. Sands 2-4 are correlated with tsunamis associated with the Eicho-Tokai, AD 1361 Shohei-Koan, and AD 1498 Meio-Tokai earthquakes, respectively. Our data indicate that a sand spit, which had previously protected the lagoon from oceanic waves, was abruptly destroyed following the AD 1096 Eicho-Tokai earthquake and did not re-form at the same location. This disappearance of the sand spit is inferred to have involved an earthquake-induced submarine landslide. The data presented in this paper, together with information obtained from historical documents, indicates that M8 megathrust earthquakes in AD 1096 and AD 1498 caused submarine landslides in the study area, resulting in coastal subsidence and damage to coastal areas additional to that caused by the tsunamis. (C) 2020 The Author(s). Published by Elsevier Ltd.

【 授权许可】

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