Development of needle penetrator test for small fragment and strength profile of subduction zone

2017 Fiscal Year Final Research Report

• Project/Area Number: 16K13892
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Geology
• Research Institution: Yamaguchi University
• Principal Investigator: SAKAGUCHI Arito 山口大学, 大学院創成科学研究科, 教授 (80304666)
• Co-Investigator(Kenkyū-buntansha): 山口 飛鳥 東京大学, 大気海洋研究所, 准教授 (30570634)
• Project Period (FY): 2016-04-01 – 2018-03-31
• Keywords: 沈み込み帯 / 震源断層 / 針貫入強度 / 南海トラフ / 応力場

Outline of Final Research Achievements

Hanging wall crust of the seismogenic zone along the Nankai Trough is composed of sediment. This study attempted to clarify stress distribution of seismogenic zone based on strain hardening behavior of sediment. The samples of small cuttings were obtained from IODP Nankai Trough drilling project, at Tonankai Earthquake of 1944 (Mw=8.1) area. Sediment strength is estimated from needle penetrator test that improved for this study. In the result, sediment strength increase with depth, and increasing rate of sediment at deep portion is higher than shallower portion. In case of basal friction model, shear stress will appear around basal fault, and stress level increase in proportion to friction level. The seismogenic fault may be close to high friction or locked condition.

Free Research Field

構造地質