Abstract
Strength and slip behaviors of subduction megathrusts are controlled by the physical properties and stress state not only of the fault zones themselves but also the adjacent wall rocks in overriding and subducting plates. In the Nankai Trough, a 3 km deep riser borehole at Integrated Ocean Drilling Program Site C0002 was drilled into the Kumano fore-arc basin and the underlying accretionary prism. We quantify the full in situ stress tensor and pore pressure at Site C0002 by integrating drilling data, geophysical logging, and downhole measurements using empirical relations that describe sediment compaction behavior as a function of loading path. The Kumano Basin is loaded in uniaxial vertical strain conditions, whereas the prism below is loaded with greater differential stress, has a modestly elevated pore pressure, and lies in a strike-slip faulting regime. This can be reconciled with slip on the megathrust fault if the horizontal stresses vary with time or depth and/or if shear stress along the megathrust is low.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 9644-9652 |
| Number of pages | 9 |
| Journal | Geophysical Research Letters |
| Volume | 44 |
| Issue number | 19 |
| DOIs | |
| State | Published - Oct 16 2017 |
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All Science Journal Classification (ASJC) codes
- Geophysics
- Earth and Planetary Sciences(all)
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In Situ Stress and Pore Pressure in the Deep Interior of the Nankai Accretionary Prism, Integrated Ocean Drilling Program Site C0002. / Kitajima, Hiroko; Saffer, Demian; Sone, Hiroki; Tobin, Harold; Hirose, Takehiro.
In: Geophysical Research Letters, Vol. 44, No. 19, 16.10.2017, p. 9644-9652.Research output: Contribution to journal › Article
TY - JOUR
T1 - In Situ Stress and Pore Pressure in the Deep Interior of the Nankai Accretionary Prism, Integrated Ocean Drilling Program Site C0002
AU - Kitajima, Hiroko
AU - Saffer, Demian
AU - Sone, Hiroki
AU - Tobin, Harold
AU - Hirose, Takehiro
PY - 2017/10/16
Y1 - 2017/10/16
N2 - Strength and slip behaviors of subduction megathrusts are controlled by the physical properties and stress state not only of the fault zones themselves but also the adjacent wall rocks in overriding and subducting plates. In the Nankai Trough, a 3 km deep riser borehole at Integrated Ocean Drilling Program Site C0002 was drilled into the Kumano fore-arc basin and the underlying accretionary prism. We quantify the full in situ stress tensor and pore pressure at Site C0002 by integrating drilling data, geophysical logging, and downhole measurements using empirical relations that describe sediment compaction behavior as a function of loading path. The Kumano Basin is loaded in uniaxial vertical strain conditions, whereas the prism below is loaded with greater differential stress, has a modestly elevated pore pressure, and lies in a strike-slip faulting regime. This can be reconciled with slip on the megathrust fault if the horizontal stresses vary with time or depth and/or if shear stress along the megathrust is low.
AB - Strength and slip behaviors of subduction megathrusts are controlled by the physical properties and stress state not only of the fault zones themselves but also the adjacent wall rocks in overriding and subducting plates. In the Nankai Trough, a 3 km deep riser borehole at Integrated Ocean Drilling Program Site C0002 was drilled into the Kumano fore-arc basin and the underlying accretionary prism. We quantify the full in situ stress tensor and pore pressure at Site C0002 by integrating drilling data, geophysical logging, and downhole measurements using empirical relations that describe sediment compaction behavior as a function of loading path. The Kumano Basin is loaded in uniaxial vertical strain conditions, whereas the prism below is loaded with greater differential stress, has a modestly elevated pore pressure, and lies in a strike-slip faulting regime. This can be reconciled with slip on the megathrust fault if the horizontal stresses vary with time or depth and/or if shear stress along the megathrust is low.
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U2 - 10.1002/2017GL075127
DO - 10.1002/2017GL075127
M3 - Article
AN - SCOPUS:85030626421
VL - 44
SP - 9644
EP - 9652
JO - Geophysical Research Letters
JF - Geophysical Research Letters
SN - 0094-8276
IS - 19
ER -