Heat flow survey in the vicinity of the branches of the megasplay fault in the Nankai accretionary prism

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doi: 10.1186/1880-5981-66-126
Author(s): Yamano, Makoto; Kawada, Yoshifumi; Hamamoto, Hideki
Author Affiliation(s): Primary:
University of Tokyo, Earthquake Research Institute, Tokyo, Japan
Other:
Center for Environmental Science in Saitama, Japan
Volume Title: Earth, Planets and Space
Source: Earth, Planets and Space, 66(1). Publisher: Terra Scientific Publishing Company (TERRAPUB), Tokyo, Japan. ISSN: 1343-8832
Note: In English. 28 refs.; illus., incl. 1 table, sketch maps
Summary: Heat flow measurements were conducted at four sites in the Nankai accretionary prism southeast of the Kii Peninsula, around the area where the megasplay fault reaches the surface, in conjunction with long-term monitoring of bottom water temperature at nearby stations. Analysis of the obtained data showed that variations in bottom water temperature seriously affect surface heat flow measurements in the areas with water depths of less than about 2,800 m. This effect can reach up to 20% to 30% and may have significantly contributed to a large scatter in the heat flow values previously measured in the study area. The temperature records were also used to determine heat flows from sediment temperature profiles disturbed by bottom water temperature variations. Results of measurements at sites deeper than 2,800 m indicate that the regional heat flow, corrected for surface disturbances including the influence of bathymetric relief, is about 65 mW/m2, which is consistent with the value calculated using subduction thermal models. Local high heat flow values were obtained in the vicinity of the tips of the branches of the splay fault, suggesting advective heat transport by upward pore fluid flow along the faults. Copyright 2014 The Author(s) and Yamano et al.; licensee Springer.
Year of Publication: 2014
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 18 Geophysics, Solid-Earth; Accretionary wedges; Advection; Bathymetry; Bottom water; Cold seeps; Depth; Expedition 316; Fault scarps; Faults; Fluid flow; Heat flow; Heat transfer; IODP Site C0004; IODP Site C0008; Integrated Ocean Drilling Program; Megasplay faults; Monitoring; NanTroSEIZE; Nankai Trough; North Pacific; Northwest Pacific; Pacific Ocean; Sediments; Splay faults; Subduction; Surveys; Temperature; West Pacific
Coordinates: N330655 N330655 E1362849 E1362849
N330610 N330610 E1363145 E1363145
N330713 N330713 E1362836 E1362836
N330720 N330720 E1362845 E1362845
Record ID: 2016108529
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by Springer Verlag, Berlin, Federal Republic of Germany