Observed stress state for the IODP Site C0002 and implication to the stress field of the Nankai Trough subduction zone

Wu, H.-Y.; Chan, Chung-Han; Shiraishi, Kazuyuki; Wspanialy, Adam; Sugihara, Takamitsu; Yukitoshi, Sanada

doi:10.1016/j.tecto.2019.04.017

Cited by 6 publications

(3 citation statements)

References 27 publications

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“…At t = 0, only the liquid phase exists, which is seawater with 3% salinity (corresponding to a chloride ion concentration of 550 mM) and no dissolved methane at any depth. Water pressure is hydrostatic and increases at a gradient of 10.4 MPa/km (Wu et al, 2019). Temperature is at a steady state and increases linearly with depth with the gradient of 43 C/km (Malinverno & Goldberg, 2015).…”

Section: Funding Informationmentioning

confidence: 99%

Simulation of methane hydrate formation in coarse‐ to fine‐grained sediments in the Nankai Trough, Japan

Xu,

Tomaru

2023

Island Arc

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The properties of host sediments and pore water considerably affect both the occurrence and formation processes of methane hydrate. In coarse‐grained layers, hydrates are generally concentrated preferentially in the pore space, and their formation is influenced by pore water salinity. To understand how geophysical and geochemical factors control the distribution of methane hydrates, we conducted numerical simulations using a one‐dimensional flow model under different reservoir and fluid conditions in the Kumano Forearc Basin, Nankai Trough, Japan. Assuming an estimated range of methane flux between 0.002 and 1.9 kg m−2 year−1, three flow scenarios were considered. When the methane flux was relatively small, the results coincided with the observed hydrate distribution. In general, a low‐methane flux decreases the hydrate saturation upward from the bottom of the methane hydrate stability, whereas a high‐methane flux increases the saturation downward. These results also suggest that the sediment structure, such as the fracture distribution, influences the sediment stress conditions and constrains the flow regime. We further examined the effects of permeability changes in the heterogeneous lithological units on the simulation results using typical permeabilities of 10−13 m2 for sand and 10−15 m2 for mud. The results showed that hydrate saturation sharply increased and decreased in adjacent high‐ and low‐permeability units, respectively. The consideration of complex stratigraphic conditions and variable fluid configurations provides an understanding of the environmental factors controlling hydrate generation and distribution, which is important for hydrate resource extraction and geohazard prevention.

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Section: Funding Informationmentioning

confidence: 99%

Simulation of methane hydrate formation in coarse‐ to fine‐grained sediments in the Nankai Trough, Japan

Xu,

Tomaru

2023

Island Arc

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“…For example, significant principal stress rotations followed the 2011 M w 9.0 Tohoku earthquake in Japan, 2010 M w 8.8 Maule earthquake in Chile, and 2004 M w 9.2 earthquake in Sumatra‐Andaman are suggested to be related to near‐complete stress drops (Hardebeck, 2012; W. Lin et al., 2023). Therefore, quantitative knowledge of stress is an essential step to characterize and understand the nature and causes of earthquake processes, the mechanical behavior of plate boundary faults, the origin and controls of diverse fault slip patterns, and to better assess seismic and tsunamigenic hazards along subduction zones (Huffman & Saffer, 2016; Riedel et al., 2016; Wu et al., 2019).…”

Section: Introductionmentioning

confidence: 99%

Shallow Tectonic Stress Magnitudes at the Hikurangi Subduction Margin, New Zealand

Behboudi,

McNamara,

Lokmer

2023

Geochem Geophys Geosyst

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Quantifying tectonic stress magnitudes is crucial in understanding crustal deformation processes, fault geomechanics, and variable plate interface slip behaviors in subduction zones. The Hikurangi Subduction Margin (HSM), New Zealand, is characterized by along‐strike variation in interface slip behavior, which may be linked to tectonic stress variations within the overriding plate. This study constrains in situ stress magnitudes of the shallow (<3 km) overriding plate of the HSM to better understand its tectonics and how they relate to larger scale subduction dynamics. Results reveal σ3: Sv ratios of 0.6–1 at depths above 650–700 m TVD and 0.92–1 below this depth interval along the entire HSM. Additionally, for depths below 650–700 m TVD, SHmax: Sv ratios of 0.95–1.81 in the central HSM and 0.95–2.3 in the southern HSM are estimated. These stress ratios suggest a prevalent thrust to strike‐slip (σ1 = SHmax) faulting regime across the central and southern HSM. In the central HSM, the presence of NNE‐NE striking reverse faults co‐existing with a modern σ1 (SHmax) aligned ENE‐WSW suggests that overtime the stress state here evolved from a contractional to a strike‐slip state, where the compressional direction changes from perpendicular (NW‐SE) to oblique (ENE‐WSW) to the Hikurangi margin. This temporal change in stress state may be explained by forearc rotation, likely combined with the development of upper plate overpressures. In the southern HSM, the modern WNW‐ESE/NW‐SE σ1 (SHmax) and pre‐existing NNE‐NE striking reverse faults indicate that stress state remains contractional and perpendicular (NW‐SE) to the Hikurangi margin overtime.

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“…For example, significant principal stress rotations followed the 2011 M w 9.0 Tohoku earthquake in Japan, 2010 M w 8.8 Maule earthquake in Chile; and 2004 M w 9.2 earthquake in Sumatra-Andaman are suggested to be related to near-complete stress drops (Hardebeck, 2012). Therefore, quantitative knowledge of stress is an essential step to characterize and understand the nature and causes of earthquake processes, the mechanical behavior of plate boundary faults, the origin and controls of diverse fault slip patterns; and to better assess seismic and tsunamigenic hazards along subduction zones (Huffman & Saffer, 2016;Riedel et al, 2016;Wu et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Shallow Tectonic Stress Magnitudes at the Hikurangi Subduction Margin, New Zealand

Behboudi¹,

McNamara

Lokmer

2022

Preprint

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Quantifying tectonic stress magnitudes is crucial in understanding crustal deformation processes, fault geomechanics, and variable plate interface slip behaviors in subduction zones. The Hikurangi Subduction Margin (HSM), New Zealand is characterized by along-strike variation in interface slip behavior, which may be linked to tectonic stress variations within the overriding plate. This study constrains in-situ stress magnitudes of the shallow (<3km) overriding plate of the HSM to better understand its tectonics and how they relate to larger scale subduction dynamics. Results reveal σ3: Sv ratios of 0.6-1 at depths above 650-700 m TVD and 0.92-1 below this depth interval along the HSM and SHmax: Sv ratios of 0.95-1.81 in the central HSM, and 0.95-3.12 in the southern HSM. These stress ratios suggest a prevalent thrust to strike-slip (σ1=SHmax) faulting regime across the central and southern HSM. In the central HSM, the presence of NNE-NE striking reverse faults co-existing with a modern σ1 aligned ENE-WSW (SHmax) suggests that overtime the stress state here evolved from a contractional to a strike-slip state, where the compressional direction changes from perpendicular (NW-SE) to subparallel (ENE-WSW) to the Hikurangi margin. This temporal change in stress state may be explained by forearc rotation, likely combined with development of upper plate overpressures. In the southern HSM, the modern WNW-ESE/ NW-SE σ1 (SHmax) and pre-existing NNE-NE striking reverse faults indicate that stress state remains contractional and subparallel (NW-SE) to the Hikurangi margin overtime. This may reflect the interseismic locked nature of the plate interface.

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Observed stress state for the IODP Site C0002 and implication to the stress field of the Nankai Trough subduction zone

Cited by 6 publications

References 27 publications

Simulation of methane hydrate formation in coarse‐ to fine‐grained sediments in the Nankai Trough, Japan

Simulation of methane hydrate formation in coarse‐ to fine‐grained sediments in the Nankai Trough, Japan

Shallow Tectonic Stress Magnitudes at the Hikurangi Subduction Margin, New Zealand

Shallow Tectonic Stress Magnitudes at the Hikurangi Subduction Margin, New Zealand

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