[M-IS33_30AM1] 巨大地震・津波のポテンシャルを現場から事前に評価できるのか？

[MIS33-03] 日本海溝下部陸側斜面のタービダイト―NT13-19次航海の成果から

*宇佐見 和子¹、池原 研¹、マクヒュー セシリア²、金松 敏也³ (1.産業技術総合研究所地質情報研究部門、2.海洋研究開発機構・Queens College, C.U.N.Y.、3.海洋研究開発機構)

キーワード：地震, 日本海溝, タービダイト, テフラ

To understand the recurrence of large earthquakes along the Japan Trench, we collected 24 sediment cores from the Japan Trench inner slope, 37.5-40 N, 143.5-144.16 E, water depth 4000-6000 m, during the NT13-19 cruise. Many deep-sea turbidites were intercalated in the sediment cores. We examined the interval and structures of the turbidites using soft-X radiographs. In general, number of the turbidites in a core is high in the southern part off Sendai, but is low in the northern part off Miyako. Meanwhile, intercalated tephras such as Haruna-Ikaho (Hr-FP), Towada-Chuseri (To-Cu) and Towada-a (To-a) were identified in the 13 cores. Based on the eruption ages of the tephras, we estimated the averaged recurrence intervals of 100-500 years in average in almost cores. But there are cores that display different intervals over 1500-2000 years.