Geometry of slab, intraslab stress field and its tectonic implication in the Nankai trough, Japan

Xu, Jiren; Kono, Yoshiteru

doi:10.1186/bf03351726

Cited by 21 publications

(21 citation statements)

References 28 publications

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“…Examples are either a localized bending within the anticlinal thrust sheets [Cai et al, 1995] as in C0001, or a much larger scale plate bending associated with subducting slab that causes a stress localization depending on characteristic geometry and motion pattern of the slab [Xu and Kono, 2002;Zhao et al, 2003]. In principle, these factors are related to inhomogeneous deformation that consequently induces local perturbation of in situ stress.…”

Section: Discussionmentioning

confidence: 99%

In situ stress state in the Nankai accretionary wedge estimated from borehole wall failures

Chang

McNeill

Moore

et al. 2010

Geochem Geophys Geosyst

124

213

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[1] We constrain the orientations and magnitudes of in situ stress tensors using borehole wall failures (borehole breakouts and drilling-induced tensile fractures) detected in four vertical boreholes (C0002, C0001, C0004, and C0006 from NW to SE) drilled in the Nankai accretionary wedge. The directions of the maximum horizontal principal stress (S Hmax ), indicated by the azimuths of borehole wall failures, are consistent in individual holes, but those in C0002 (margin-parallel S Hmax ) are nearly perpendicular to those in all other holes (margin-normal S Hmax ). Constrained stress magnitudes in C0001 and C0002, using logged breakout widths combined with empirical rock strength derived from sonic velocity, as well as the presence of the drilling-induced tensile fractures, suggest that the stress state in the shallow portion of the wedge (fore-arc basin and slope sediment formations) is predominantly in favor of normal faulting and that the stress state in the deeper accretionary prism is in favor of probable strike-slip faulting or possible reverse faulting. Thus, the stress regime appears to be divided with depth by the major geological boundaries such as unconformities or thrust faults. The margin-perpendicular tectonic stress components in the two adjacent sites, C0001 and C0002, are different, suggesting that tectonic force driven by the plate pushing of the Philippine Sea plate does not uniformly propagate. Rather, the stress field is inferred to be influenced by additional factors such as local deformation caused by gravitation-driven extension in the fore arc and thrusting and bending within individual geologic domains.

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Section: Discussionmentioning

confidence: 99%

In situ stress state in the Nankai accretionary wedge estimated from borehole wall failures

Chang

McNeill

Moore

et al. 2010

Geochem Geophys Geosyst

124

213

View full text Add to dashboard Cite

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“…It is possible, therefore, that the lack of high-resolution locations along the Hellenic subduction zone hides the existence of a DWBZ and leads to the observed heterogeneity in sector 4. Two types of stress fields have been identified in the Nankai subduction zone (Xu and Kono, 2002); these have been explained by differences in the geometry and age of the subducting zone.…”

Section: Discussionmentioning

confidence: 99%

Slab stress field in the Hellenic subduction zone as inferred from intermediate-depth earthquakes

et al. 2011

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The stress regime across the Hellenic subduction zone was investigated by performing stress inversion on 100 intermediate-depth moment tensor solutions. In this study, the slab was divided into four sectors based on earthquake distribution, trench geometry, and the results of a previous study of slab geometry. For the Peloponnese sector, moment tensors reaching 80 km depth were inverted, and the slab stresses were compatible with a possible slab tear. For the Kithira-Western Crete and Crete sectors, homogeneity was observed at depths up to 100 and 80 km, respectively. For these two areas, the subvertical σ 3 and along-strike σ 1 justify slab rollback as the driving mechanism. The differences in the stress regime and azimuth of the maximum compression of these two sectors may reflect a bulge in the slab. For the fourth sector, Karpathos-Rhodes, two distinct subsectors were defined along a depth gradient (50-90 km and 90-180 km, respectively). The strong heterogeneity observed at both depths and changes in the stress regime from slab pull to extension may be an indication of a double WadatiBenioff zone. The membrane strain model presented here can provide a possible explanation for the along-strike compression observed at the top 90 km in three of the four sectors.

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“…It is a younger subduction history that dip angle of subduction is about 10 ± 3 • [44]. The younger subduction motions encounter strong resistance from the front plate [45,46]. The seismic velocity beneath the NSSB is less than that beneath the central plateau [47].…”

Section: Discussionmentioning

confidence: 99%

Extensional Seismogenic Stress and Tectonic Movement on the Central Region of the Tibetan Plateau

Zhao

2009

International Journal of Geophysics

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Various earthquake fault types, mechanism solutions and stress fields, as well as GPS and geothermal data are analyzed for the study of the crustal movements on the Tibetan plateau and their tectonic implications. The results show that a lot of the normal faulting type-event concentrated at altitudes greater than 4000 m on the central Tibetan plateau. The altitudes concentrating normal faulting type-events can be zoned two parts: the western part, the Lhasa block, and the eastern part, the QiangtangChangdu region. The azimuths of T-axes are in a general E-W direction in the Lhasa block and NW-SE or NNW-SSE in the Qiangtang-Changdu region at the altitudes of the Tibetan plateau. The tensional stresses in E-W direction and NW-SE direction predominate normal faulting earthquake occurrence in the Lhasa block and the Qiangtang-Changdu region, respectively. The slipping displacements of the normal-faulting-type events have great components in near E-W direction and NW-SE direction in the Lhasa block and the Qiangtang-Changdu region, respectively. The extensions are probably an eastward or southeastward extensional motion, being mainly tectonic activity phenomena in the plateau altitudes. The extensional motions due to normalfault earthquakes are important tectonic activity regimes on the high altitudes of the plateau. The easterly crustal extensions on the plateau are attributable to the gravitational collapse of the high plateau and eastward extrusion of hotter mantle materials beneath the eastern boundary of the plateau. Numbers of thrust-fault and strike-slip-fault earthquakes with strong compressive stress in a general NNE-SSW direction occur on the edges of the plateau.

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Geometry of slab, intraslab stress field and its tectonic implication in the Nankai trough, Japan

Cited by 21 publications

References 28 publications

In situ stress state in the Nankai accretionary wedge estimated from borehole wall failures

In situ stress state in the Nankai accretionary wedge estimated from borehole wall failures

Slab stress field in the Hellenic subduction zone as inferred from intermediate-depth earthquakes

Extensional Seismogenic Stress and Tectonic Movement on the Central Region of the Tibetan Plateau

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