Stress states at the subduction input site, Nankai subduction zone, using anelastic strain recovery (ASR) data in the basement basalt and overlying sediments

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doi: 10.1016/j.tecto.2013.01.028
Author(s): Yamamoto, Yuzuru; Lin, Weiren; Oda, Hirokuni; Byrne, Timothy; Yamamoto, Yuhji
Author Affiliation(s): Primary:
Japan Agency for Marine-Earth Science and Technology, Institute for Research on Earth Evolution, Yokohama, Japan
Other:
Geological Survey of Japan, Japan
University of Connecticut, United States
Kochi University, Japan
Volume Title: Great earthquakes along subduction zones
Volume Author(s): Kimura, Gaku, editor; Brodsky, Emily; Di Toro, Giulio; Ide, Satoshi; Kanagawa, Kyuichi; Park, Jin-Oh; Underwood, Michael
Source: Great earthquakes along subduction zones, edited by Gaku Kimura, Emily Brodsky, Giulio Di Toro, Satoshi Ide, Kyuichi Kanagawa, Jin-Oh Park and Michael Underwood. Tectonophysics, Vol.600, p.91-98. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0040-1951 CODEN: TCTOAM
Note: In English. 20 refs.; illus., incl. 2 tables, sketch map
Summary: The three-dimensional orientations of stress and stress magnitudes in the basement basalt and overlying sediments at the subduction input site, IODP Site C0012, have been determined using anelastic strain recovery (ASR) analyses. The ASR results in the sedimentary sequence indicate that σ1 is nearly vertical. The magnitudes of σ2 and σ3 are very similar, indicating that the stress state in the sedimentary sequence is "at rest". On the other hand, ASR analyses in the basement basalt show that σ1 is nearly horizontal and oriented NE-SW, almost parallel (or slightly oblique) to the trench axis. σ3 plunges moderately to the NW. The stress state of the basement basalts suggests a strike-slip or thrust (reverse fault) regime, which is very different from a "state at rest" condition, which is the theoretical stress condition for the ocean floor far from a subduction zone. The basement basalt at the subduction input site (C0012) has experienced trench-parallel compression and trench-normal extension, consistent with the focal mechanisms of earthquakes in the vicinity. The estimated stress magnitudes show only small variations between the principal stresses, implying that the directions of principal stress could be easily rotated in association with any tectonically induced local stress variation. The stress orientation in the basement basalt seems to be the result of hinge extension during bending of the Philippine Sea Plate, either in association with subduction or with the formation of an anticline during intraoceanic thrusting. Abstract Copyright (2013) Elsevier, B.V.
Year of Publication: 2013
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 16 Structural Geology; Anelasticity; Anticlines; Basalts; Basement; Cenozoic; Compression tectonics; Crust; Deformation; Earthquakes; Expedition 322; Extension tectonics; Faults; Focal mechanism; Folds; IODP Site C0002; IODP Site C0012; Igneous rocks; Integrated Ocean Drilling Program; Kumano Basin; Lithofacies; Lithostratigraphy; Lower Miocene; Lower Pliocene; Marine sediments; Mathematical methods; Miocene; NanTroSEIZE; Nankai Trough; Neogene; North Pacific; Northwest Pacific; Ocean floors; Oceanic crust; Pacific Ocean; Philippine Sea Plate; Plate tectonics; Pliocene; Sediments; Shikoku Basin; Strain; Stress fields; Strike-slip faults; Subduction zones; Tectonics; Tertiary; Three-dimensional models; Thrust faults; Trenches; Volcanic rocks; West Pacific
Coordinates: N324400 N325000 E1365600 E1365200
N324400 N334500 E1370000 E1363000
Record ID: 2014001329
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands