Extension of continental crust by anelastic deformation during the 2011 Tohoku-oki earthquake: The role of extensional faulting in the generation of a great tsunami

Tsuji, Takeshi; Kawamura, Kazutaka; Kanamatsu, Toshiya; Kasaya, Takafumi; Fujikura, Katsunori; Ito, Yoshihiro; Tsuru, Takeshi Go; Kinoshita, Masataka

doi:10.1016/j.epsl.2012.12.038

Cited by 80 publications

(86 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At C0002 the reorientation of 3 relative to the regional pattern may reflect gravitation collapse of the prism as the décollement weakens either continuously or during large earthquakes as suggested for the Tohoku region (McKenzie and Jackson, 2012; Kimura et al, 2012;Tsuji et al, 2013). A seismic reflection profile running NW-SE and including Site C0002 displays a clear sequence of trough-parallel normal faults in the basin sediments consistent with the maximum horizontal stress orientation data (e.g.…”

Section: Discussion: Nankai Marginmentioning

confidence: 74%

“…Tobin and Saffer, 2009;Kitajima et al, 2012;Hashimoto et al, 2013;Tsuji et al, 2014). Tsuji et al (2013), based on sea floor observations of extension cracks and heat flow anomalies, also propose that normal faulting in the hanging wall occurred simultaneously with slip on the décollement. Along the Nankai margin, the décollement is also interpreted to be anomalously weak and the seaward edge of the Kumano Basin is deformed exclusively by normal faults, suggesting a tectonic setting similar to Tohoku.…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

See 1 more Smart Citation

Distribution of stress state in the Nankai subduction zone, southwest Japan and a comparison with Japan Trench

et al. 2016

Self Cite

View full text Add to dashboard Cite

Abstract:To better understand the distribution of three dimensional stress states in the Nankai subduction zone, southwest Japan, we review various stress-related investigations carried out in the first and second stage expeditions of the Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) by the Integrated Ocean Drilling Program (IODP) and compile the stress data. Overall, the maximum principal stress 1 in the shallower levels (<~1km) is vertical from near the center of forearc basin to near the trench and; the maximum horizontal stress SHmax (interpreted to be the intermediate principal stress 2) is generally parallel to the plate convergence vector. The exception to this generalization occurs along the shelf edge of the Nankai margin where SHmax is along strike rather than parallel to the plate convergence vector. Reorientation of the principal stresses at deeper levels (e.g., >~1km below seafloor or in underlying accretionary prism) with 1 becoming horizontal is also suggested at all deeper drilling sites. We also make a comparison of the stress state in the hanging wall of the frontal plate-interface between Site C0006 in the Nankai and Site C0019 in the Japan Trench subduction zone drilled after the 2011 Mw9.0 Tohoku-Oki earthquake. In the Japan Trench, the A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT3 comparison between stress state before and after the 2011 mega-earthquake shows that the stress changed from compression before the earthquake to extension after the earthquake. As a result of the comparison between the Nankai Trough and Japan Trench, a similar current stress state with trench parallel extension was recognized at both C0006 and C0019 sites. Hypothetically, this may indicate that in Nankai Trough it is still in an early stage of the interseismic cycle of a great earthquake which occurs on the décollement and propagates to the toe (around site C0006).

show abstract

Section: Discussion: Nankai Marginmentioning

confidence: 74%

Section: Accepted M Manuscriptmentioning

confidence: 99%

Distribution of stress state in the Nankai subduction zone, southwest Japan and a comparison with Japan Trench

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…Our PSDM image (Figures 3a and 4) shows a relatively transparent frontal prism, although several landward dipping discontinuous reflections can be distinguished (Figure 4). Some of these reflections extend from the plate boundary to the seafloor and have been previously interpreted as reverse faults (e.g., Tsuji et al 2013); however, the lack of stratigraphy in the frontal prism makes it difficult to determine the sense of slip. The seismic velocity within the frontal prism is approximately 2.0 km/s in average and 2.5 km/s at maximum (Figure 3c).…”

Section: Discussionmentioning

confidence: 99%

Seismic imaging and velocity structure around the JFAST drill site in the Japan Trench: low Vp, high Vp/Vs in the transparent frontal prism

Nakamura

Kodaira

Cook

et al. 2014

Earth, Planets and Space

Self Cite

View full text Add to dashboard Cite

Seismic image and velocity models were obtained from a newly conducted seismic survey around the Integrated Ocean Drilling Program (IODP) Japan Trench Fast Drilling Project (JFAST) drill site in the Japan Trench. Pre-stack depth migration (PSDM) analysis was applied to the multichannel seismic reflection data to produce an accurate depth seismic profile together with a P wave velocity model along a line that crosses the JFAST site location. The seismic profile images the subduction zone at a regional scale. The frontal prism where the drill site is located corresponds to a typically seismically transparent (or chaotic) zone with several landward-dipping semi-continuous reflections. The boundary between the Cretaceous backstop and the frontal prism is marked by a prominent landward-dipping reflection. The P wave velocity model derived from the PSDM analysis shows low velocity in the frontal prism and velocity reversal across the backstop interface. The PSDM velocity model around the drill site is similar to the P wave velocity model calculated from the ocean bottom seismograph (OBS) data and agrees with the P wave velocities measured from the core experiments. The average Vp/Vs in the hanging wall sediments around the drill site, as derived from OBS data, is significantly larger than that obtained from core sample measurements.

show abstract

“…Because the outer and inner wedges can behave differently during an earthquake cycle (Wang and Hu 2006), the transition zone functions as a stress boundary. Furthermore, the transition zone is a key region for evaluation of the potential of coseismic rupture propagation close to the trough axis, which may generate large tsunamis (Satake 1994;Gulick et al 2011;Tsuji et al 2013;Moeremans et al 2014). Recent studies based on high-resolution seismic velocity and pore pressure distribution have demonstrated that a deep mega-splay fault continues to the seaward (trenchward) décollement and functions as a detachment fault (Figure 2; Kamei et al 2012;Tsuji et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Strike-slip motion of a mega-splay fault system in the Nankai oblique subduction zone

Tsuji

Ashi

Ikeda

2014

Earth, Planets and Space

Self Cite

View full text Add to dashboard Cite

We evaluated the influence of the trench-parallel component of plate motion on the active fault system within the Nankai accretionary wedge from reflection seismic profiles, high-resolution seafloor bathymetry, and deep-towed sub-bottom profiles. Our study demonstrated that a large portion of the trench-parallel component of oblique plate subduction is released by strike-slip motion along a fault located just landward of and merging down-dip with a mega-splay fault. The shallow portion of the splay fault system, forming a flower structure, seems to accommodate dominant strike-slip motion, while most of the dip-slip motion could propagate to the trenchward décollement. Numerous fractures developed around the strike-slip fault release overpressured pore fluid trapped beneath the mega-splay fault. The well-developed fractures could be related to the change in stress orientation within the accretionary wedge. Therefore, the strike-slip fault located at the boundary between the inner and outer wedges is a key structure controlling the stress state (including pore pressure) within the accretionary prism. In addition, the strike-slip motion contributes to enhancing the continuous mega-splay fault system (outer ridge), which extends for approximately 200 km parallel to the Nankai Trough.

show abstract

Extension of continental crust by anelastic deformation during the 2011 Tohoku-oki earthquake: The role of extensional faulting in the generation of a great tsunami

Cited by 80 publications

References 46 publications

Distribution of stress state in the Nankai subduction zone, southwest Japan and a comparison with Japan Trench

Distribution of stress state in the Nankai subduction zone, southwest Japan and a comparison with Japan Trench

Seismic imaging and velocity structure around the JFAST drill site in the Japan Trench: low Vp, high Vp/Vs in the transparent frontal prism

Strike-slip motion of a mega-splay fault system in the Nankai oblique subduction zone

Contact Info

Product

Resources

About