Tracing geologically constrained fluid flow pathways using a combination of heat flow measurements, pore water chemistry, and acoustic imaging near the deformation front of the Nankai Trough off the Muroto Peninsula, Japan

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doi: 10.1016/j.tecto.2014.01.035
Author(s): Kawada, Yoshifumi; Toki, Tomohiro; Kinoshita, Masataka; Joshima, Masato; Higa, Ryosaku; Kasaya, Takafumi; Tsunogai, Urumu; Nishimura, Kiyokazu; Kisimoto, Kiyoyuki
Author Affiliation(s): Primary:
University of Tokyo, Earthquake Research Institute, Tokyo, Japan
Other:
University of the Ryukyus, Japan
Institute for Research on Earth Evolution, Japan
Geological Survey of Japan, Japan
Hokkaido University, Japan
Volume Title: Tectonophysics
Source: Tectonophysics, Vol.618, p.121-137. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0040-1951 CODEN: TCTOAM
Note: In English. Includes appendices. 51 refs.; illus., incl. 1 table, sketch maps
Summary: Visual and acoustic surveys, heat flow measurements, and the analysis of pore water chemistry near the deformation front of the Nankai Trough accretionary prism off the Muroto Peninsula, Japan, show that fluid discharge is constrained by geological structures such as landslides. High heat-flow anomalies (up to 260 mWm-2) exist near the base of a ca. 1.5 km ridge-trough structure, where the exit point of the secondary frontal thrust is thought to occur, but no other anomalies were detected. In contrast, on a 50-m-wide flat area on the steep slope inside the slope-scale landslide structure, where geological strata are exposed, high heat-flow anomalies of around 190 mWm-2 exist, accompanied by biological activity and methane-rich pore water. A sub-bottom profiler recorded strata cutting through the seafloor, which also supports the existence of a landslide. Based on these results, we propose a qualitative picture of fluid flow that may explain the observed heat-flow anomalies. Upward fluid flow through the frontal thrust, fluid flow cutting through geological strata, is inhibited near the foot of the slope, while fluid discharge occurs where the landslide exposes new surfaces as a result of geologically constrained fluid flow along strata. Abstract Copyright (2014) Elsevier, B.V.
Year of Publication: 2014
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 18 Geophysics, Solid-Earth; Accretionary wedges; Acoustical methods; Aliphatic hydrocarbons; Alkanes; Anomalies; Asia; Bathymetry; Biogenic processes; Chemical composition; Deformation; Far East; Faults; Geophysical methods; Geophysical surveys; Heat flow; Hydrocarbons; Japan; Methane; Models; Muroto Peninsula; Nankai Trough; North Pacific; Northwest Pacific; ODP Site 808; Ocean Drilling Program; Organic compounds; Pacific Ocean; Pore water; Shikoku; Surveys; Thrust faults; West Pacific
Coordinates: N320000 N333000 E1350500 E1341000
Record ID: 2014065833
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands