Source mechanisms and tectonic significance of historical earthquakes along the nankai trough, Japan

Ando, Masataka

doi:10.1016/0040-1951(75)90102-x

Cited by 1,037 publications

(771 citation statements)

References 8 publications

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“…The convergence direction is approximately normal to the trench, and sediments of the Shikoku Basin are actively accreting at the deformation front. The Nankai Trough is among the most extensively studied subduction zones in the world, and great earthquakes during the past 3000 or more years are well documented in historical and archeological records (e.g., Ando, 1975). The Nankai Trough has been selected as a focus site for studies of seismogenesis by both IODP and the U.S. MARGINS initiative, based on the wealth of geological and geophysical data available, a long historical record of great (M >8.0) earthquakes, and direct societal relevance of understanding tsunamis and earthquakes that have had, and will have, great impact on nearby heavily populated coastal areas.…”

Section: Background Geological Settingmentioning

confidence: 99%

Untitled

Kimura¹,

Screaton²,

Curewitz³

et al. 2008

IODP Preliminary Report

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Section: Background Geological Settingmentioning

confidence: 99%

Untitled

Kimura¹,

Screaton²,

Curewitz³

et al. 2008

IODP Preliminary Report

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“…While the segment boundary limits the rupture area of an individual earthquake, sometimes a great earthquake across a segment boundary occurs, causing strong shaking and devastating tsunamis, e.g., Nankai (Ando, 1975), Cascadia (Satake et al, 1996), Chile (Campos et al, 2002), Kuril (Sawai et al, 2004), Sumatra (Lay et al, 2005), and Japan Trench (Ide et al, 2011). However, except for recent earthquakes such as the 2004 Sumatra (M 9.2), whether or not a great earthquake occurred across a segment boundary may be controversial, because it often depends solely on historical documents.…”

Section: Introductionmentioning

confidence: 99%

“…Historically, great megathrust earthquakes with a recurrence interval of 100-200 yr (e.g., Ando, 1975) have generated strong motions and large tsunamis along the Nankai Trough margin. In particular, the Nankai subduction zone off Kii Peninsula (Fig.…”

Section: Introductionmentioning

confidence: 99%

“…Based on historical documents and observation on subduction thrust earthquake occurrence, the Nankai subduction zone is segmented into ve different domains, i.e., A, B, C, D, and E (Ando, 1975), each of which roughly corresponds to a geologically well-de ned forearc basin (Sugiyama, 1994). The earthquake rupture pattern over those ve segments suggests that a boundary between segments A-B and C-D has been stable over the historic earthquake cycles.…”

Section: Introductionmentioning

confidence: 99%

“…However, it has been controversial whether, or not, there has been an earthquake rupture Inset: Regional map showing the location of the study area (red box). The Nankai subduction zone may be divided into five discrete segments (A through E) (Ando, 1975 (Obara and Ito, 2005). Green circles are cold seeps (Ashi et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

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Seismic reflection and bathymetric evidences for the Nankai earthquake rupture across a stable segment-boundary

Park

Kodaira

2012

Earth Planet Sp

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Seismic re ection pro les reveal steeply landward-dipping splay faults in segment B (the 1946 Nankai earthquake rupture, M 8.3) as well as segment C (the 1944 Tonankai earthquake rupture, M 8.1) of the Nankai subduction zone. The splay faults, branching upward from the plate-boundary interface, almost reach the sea oor, producing sea oor fault scarps. The swath-bathymetry map exhibits a ∼200-km-long, remarkable sea oor lineament with which the sea oor fault scarps align in the segments B and C. The sea oor lineament, which we believe is produced by repeating slips on the splay faults, is almost laterally continuous across a stable boundary off Kii Peninsula inbetween the two segments. These sea oor and subsurface features could be due to multiple, simultaneous coseismic slips across the B-C boundary, when subduction thrust earthquakes accompany the coseismic slips on the splay fault. The splay faults are associated with (1) uid expulsion, (2) dynamic deformation, and (3) tsunami generation.

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PandSwave velocity measurements of water-rich sediments from the Nankai Trough, Japan

Schumann

Behrmann

Klaeschen

et al. 2014

J. Geophys. Res. Solid Earth

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Acoustic velocities were measured during triaxial deformation tests of silty clay and clayey silt core samples from the Nankai subduction zone (Integrated Ocean Drilling Program Expeditions 315, 316, and 333). We provide a new data set, continuously measured during pressure increase and subsequent axial deformation. A new data processing method was developed using seismic time series analysis. Compressional wave velocities (V p ) range between about 1450 and 2200 m/s, and shear wave velocities (V s ) range between about 150 and 800 m/s. V p slightly increases with rising effective confining pressure and effective axial stress. Samples from the accretionary prism toe show the highest Vp, while fore-arc slope sediments show lower Vp. Samples from the incoming plate, slightly richer in clay minerals, have the lowest values for V p . V s increases with higher effective confining pressures and effective axial stress, irrespective of composition and tectonic setting. Shear and bulk moduli are between 0.2 and 1.3 GPa, and 3.85 and 8.41 GPa, respectively. Elastic moduli of samples from the accretionary prism toe and the footwall of the megasplay fault (1.50 and 3.98 GPa) are higher than those from the hanging wall and incoming plate (0.59 and 0.88 GPa). This allows differentiation between normal and overconsolidated sediments. The data show that in a tectonosedimentary environment of only subtle compositional differences, acoustic properties can be used to differentiate between stronger (accretionary prism toe) and weaker (fore-arc slope, incoming plate) sediments. Especially V p /V s ratios may be instrumental in detecting zones of low effective stress and thus high pore fluid pressure.

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Source mechanisms and tectonic significance of historical earthquakes along the nankai trough, Japan

Cited by 1,037 publications

References 8 publications

Untitled

Untitled

Seismic reflection and bathymetric evidences for the Nankai earthquake rupture across a stable segment-boundary

PandSwave velocity measurements of water-rich sediments from the Nankai Trough, Japan

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