Applications of anelastic strain recovery measurement for determining in-situ stress state in IODP NanTroSEIZE stage II expeditions

Author(s): Lin, Weiren; Yamamoto, Yuzuru; Byrne, Timothy B.; Yamamoto, Yuhji; Oda, Hirokuni
Author Affiliation(s): Primary:
Japan Agency for Marine-Earth Science and Technology, Japan
Other:
University of Connecticut, United States
Kochi University, Japan
National Institute of Advanced Industrial Science and Technology, Japan
Volume Title: 34th international geological congress; abstracts
Source: International Geological Congress [International Geological Congress, Abstracts = Congrès Géologique International, Résumés, Vol.34, p.305; 34th international geological congress, Brisbane, Queensl., Australia, Aug. 5-10, 2012. Publisher:], [location varies], International CODEN: IGABBY
Note: In English. Accessed on June 17, 2014
Summary: The IODP NanTroSEIZE drilling project is ongoing in Nankai Trough region across the southwest Japan subduction zone to understand the physics of an active fault where great earthquakes more than M8 occur in 100-200 years intervals. Three-dimensional in-situ stress measurements were tried by using a core-based method, i.e. anelastic strain recovery (ASR) measurement in the drilling site C9 of Exp 319 and site C12 of Exp 322 in NanTroSEIZE stage II. The site C9 locates on landward plate above the seismogenic zone of the plate boundary fault; whereas the site C12 on the subducting oceanic plate. The lithology of cores from C9 and shallow part of C12 was mudstone or siltstone with larger porosities ranged from 35% to 45%; one from deep part of C12 was basalt. We carried ASR measurements by strain gauges onboard D/V Chikyu, and successfully obtained high quality ASR data. Thus, we determined the three-dimensional stress orientations through core orientation determined by paleo-magnetism data. The stress orientations obtained from ASR tests were consistent with those from drilling induced borehole breakouts and tensile fractures.
Year of Publication: 2012
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 19 Geophysics, Seismology; Active faults; Anelasticity; Basalts; Clastic rocks; Cores; Earthquakes; Expedition 319; Expedition 322; Faults; Great earthquakes; IODP Site C0009; IODP Site C0012; Igneous rocks; Integrated Ocean Drilling Program; NanTroSEIZE; North Pacific; Northwest Pacific; Orientation; Pacific Ocean; Plate tectonics; Porosity; Sedimentary rocks; Shikoku Basin; Strain; Stress; Subduction; Subduction zones; Tensile strength; Volcanic rocks; West Pacific
Coordinates: N332728 N332728 E1363209 E1363209
N324453 N324453 E1365501 E1365501
Record ID: 2014083199
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