Stress magnitude and orientation in deep coalbed biosphere off Shimokita ≈IODP Expedition337 drilling project

Author(s): Wu, H. Y.; Lin, W.; Yamada, Y.
Author Affiliation(s): Primary:
Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science and Technology, Kanagawa, Japan
Volume Title: AGU 2015 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2015; American Geophysical Union 2015 fall meeting, San Francisco, CA, Dec. 14-18, 2015. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: One of IODP expedition (Borehole C0020A) is located in the forearc basin formed by the subducting between Pacific plate and Eurasian plate off Shimokita Peninsula. This ≈2.5km deep scientific drilling collected the high-resolution wire-line resistivity logging, caliper data, Dipole Sonic waveforms; geophysical properties measurements and core samples. The riser drilling operations produced one good conditions borehole even this drilling operation was applied right after 311 Tohoku earthquake. Based on the high-resolutions Formation Micro Imager (FMI) images, both breakout and tensile fractures along the borehole wall indicating the in-situ stress orientation are detected in the unwrapped resistivity images. In this research, a reasonable geomechanical model based on the breakout width and physical properties is constructed to estimate the stress magnitude profile in this borehole. Besides, the openhole leak-off test revealed the information of Shmin magnitude. In general, stress direction along the borehole is slight rotated to east with drilling to the bottom of the borehole. Geomechanical model constarined the principal stresses in Strike-slip stress regime to satisfy the occurrences of borehole enlargements and tensile fractures. Some blank zones with no borehole wall failure and vertical fractures indicated the stress anomaly might be controlled by local lithological facies. Comparing to the JFAST drilling, this site is out of Japan trench slip zone and shows almost parallel stress direction to the trench (≈90 degree apart of Shmin with Site C0019).
Year of Publication: 2015
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; Aomori Japan; Asia; Coal seams; Expedition 337; Far East; Honshu; IODP Site C0020; Integrated Ocean Drilling Program; Japan; Japan Trench; Japan Trench Fast Drilling Project; Magnetic properties; North Pacific; Northwest Pacific; Pacific Ocean; Shimokita Peninsula; West Pacific
Coordinates: N411036 N411036 E1421202 E1421202
Record ID: 2016072411
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