Present-day principal horizontal stress orientations in the Kumano forearc basin of the southwest Japan subduction zone determined from IODP NanTroSEIZE drilling Site C0009

Weiren Lin (1) , Mai-Linh Doan (2) , J. Casey Moore (3) , Lisa Mcneill (4) , Timothy B. Byrne (5) , Takatoshi Ito (6) , Demian Saffer (7) , Marianne Conin (8) , Masataka Kinoshita (9) , Yoshinori Sanada (10) , Kyaw Thu Moe (10) , Eiichiro Araki (9) , Harold Tobin (11) , David Boutt (12) , Yasuyuki Kano (13) , Nicholas W. Hayman (14) , Peter Flemings (14) , Gary J. Huftile (15) , Deniz Cukur (16) , Christophe Buret (17) , Anja M. Schleicher (18) , Natalia Efimenko (19) , Kuniyo Kawabata (20) , David M. Buchs (21) , Shijun Jiang (22) , Koji Kameo (23) , Keika Horiguchi (24) , Thomas Wiersberg (25) , Achim Kopf (26) , Kazuya Kitada (9) , Nobuhisa Eguchi (10) , Sean Toczko (10) , Kyoma Takahashi (10) , Yukari Kido (10)

1 Kochi Institute for Core Sample Research
2 LGIT - Laboratoire de Géophysique Interne et Tectonophysique
3 Department of Earth and Planetary Sciences [Santa Cruz]
4 NOC - National Oceanography Centre [Southampton]
5 Center for Integrative Geosciences
6 Institute of Fluid Science
7 Department of Geology and Geophysics [Laramie]
8 CEREGE - Centre européen de recherche et d'enseignement des géosciences de l'environnement
9 IFREE - Institute for Research on Earth Evolution [Yokosuka]
10 Center for Deep Earth Exploration
11 Department of Geoscience
12 Department of Geosciences
13 Research Center for Earthquake Prediction
14 IG - Institute of Geophysics [Austin]
15 Biogeosciences Discipline
16 IFM-GEOMAR - Leibniz-Institut für Meereswissenschaften
17 Laboratoire de Géologie
18 Department of Geological Sciences [Ann Arbor]
19 Institut de Géologie et de Paléontologie
20 Institute of Geophysics [Taïwan]
21 RSES - Research School of Earth Sciences [ANU, Canberra]
22 Geological Sciences
23 Department of Earth Sciences [Chiba]
24 Department of Earth and Space Science [Toyonaka-shi]
25 Section 4.2
26 MARUM - Center for Marine Environmental Sciences [Bremen]

A 1.6 km riser borehole was drilled at site C0009 of the NanTroSEIZE, in the center of the Kumano forearc basin, as a landward extension of previous drilling in the southwest Japan Nankai subduction zone. We determined principal horizontal stress orientations from analyses of borehole breakouts and drilling-induced tensile fractures by using wireline logging formation microresistivity images and caliper data. The maximum horizontal stress orientation at C0009 is approximately parallel to the convergence vector between the Philippine Sea plate and Japan, showing a slight difference with the stress orientation which is perpendicular to the plate boundary at previous NanTroSEIZE sites C0001, C0004 and C0006 but orthogonal to the stress orientation at site C0002, which is also in the Kumano forearc basin. These data show that horizontal stress orientations are not uniform in the forearc basin within the surveyed depth range and suggest that oblique plate motion is being partitioned into strike-slip and thrusting. In addition, the stress orientations at site C0009 rotate clockwise from basin sediments into the underlying accretionary prism.

Domaines: Géophysique [physics.geo-ph]; Géophysique [physics.geo-ph]; Milieux et Changements globaux

Weiren Lin, Mai-Linh Doan, J. Casey Moore, Lisa Mcneill, Timothy B. Byrne, et al.. Present-day principal horizontal stress orientations in the Kumano forearc basin of the southwest Japan subduction zone determined from IODP NanTroSEIZE drilling Site C0009. Geophysical Research Letters, 2010, 37, pp.13303. ⟨10.1029/2010GL043158⟩. ⟨insu-00565053⟩