Coseismic deformation of the Mid Niigata prefecture Earthquake in 2004 detected by RADARSAT/InSAR

Ozawa, Taku; Nishimura, Sou; Wada, Yutaka; Ohkura, H.

doi:10.1186/bf03351828

Cited by 19 publications

(8 citation statements)

References 9 publications

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“…from leveling and GPS observations (Geographical Survey Institute, 2004) and with those derived from crustal deformation detected using SAR interferometry (Ozawa et al, 2005). This supports that the JHD relocation could improve the absolute locations of the hypocenters.…”

Section: Discussionsupporting

confidence: 61%

Aftershock distribution of the 2004 Mid Niigata Prefecture Earthquake derived from a combined analysis of temporary online observations and permanent observations

et al. 2005

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The 2004 Mid Niigata Prefecture Earthquake (Mj = 6.8) occurred on 23 October 2004 in the northeastern part of the Niigata-Kobe Tectonic Zone where large contraction rates were observed. The mainshock was followed by an anomalously intense aftershock activity that included nine Mj ≥ 5.5 aftershocks. We deployed three temporary online seismic stations in the aftershock area from 27 October, combined data from the temporary stations with those from permanent stations located around the aftershock area, and determined the hypocenters of the mainshock and aftershocks with a joint hypocenter determination (JHD) technique. The resulting aftershock distribution showed that major events such as the mainshock, the largest aftershock (Mj = 6.5), the aftershock on 27 October (Mj = 6.1), etc. occurred on different fault planes that were located nearly parallel or perpendicular to each other. This might be due to heterogeneous structure in the source region. The strain energy was considered to have been enough accumulated on the individual fault planes. These features are probably a cause of the anomalous intensity of the aftershock activity.

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Section: Discussionsupporting

confidence: 61%

Aftershock distribution of the 2004 Mid Niigata Prefecture Earthquake derived from a combined analysis of temporary online observations and permanent observations

et al. 2005

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“…Tomographic analysis of aftershock data shows that the P wave velocity of the hanging wall is slower than that of the footwall [ Kato et al , 2005a, 2006; Korenaga et al , 2005; Okada et al , 2005]. Analyses of coseismic crustal deformation [ Ozawa et al , 2005] and strong ground motion records [ Hikima and Koketsu , 2005; Honda et al , 2005] support the high‐angle fault model. The aftershocks extended for a distance along strike of 35 km, from the northern end of the Higashiyama anticline to the southern termination of the Tamugiyama anticline (Figures 3 and 5).…”

Section: The 2004 Mid‐niigata Earthquakementioning

confidence: 99%

Fault‐related folds above the source fault of the 2004 mid‐Niigata Prefecture earthquake, in a fold‐and‐thrust belt caused by basin inversion along the eastern margin of the Japan Sea

Okamura¹,

Ishiyama²,

Yanagisawa³

2007

J. Geophys. Res.

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[1] The 2004 mid-Niigata Prefecture earthquake occurred in a fold-and-thrust belt that has been growing since late Pliocene time in a Miocene rift basin along the eastern margin of the Japan Sea. We constructed the trajectory of the subsurface faults responsible for the growth of the folds from the geologic structure and stratigraphy in the source region, assuming that the folds have been growing as fault-related folds because of inclined antithetic shear with a dip of 85°in the hanging wall above a single reverse fault. The fault trajectory constructed from the fold geometries nearly coincides with the geometries of the source fault of the main shock of the 2004 earthquake revealed by aftershocks, which supports that the rupture was along a geologic fault that has ruptured repeatedly during the last a few million years. A three-dimensional fault model based on 12 fault trajectories constructed along parallel sections revealed that the main shock occurred on a convex bend in the fault surface and that the southern termination of the aftershock distribution nearly coincides with a concave bend in the fault. The close relation between the source fault and the geologic structure shows that it is possible to construct source fault geometry assuming inclined shear as deformation mechanism of a hanging wall and to infer the rupture areas from geologic data.

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“…Hashimoto et al 1996), the M6.8 Mid Niigata prefecture earthquake in 2004 (e.g. Ozawa et al 2005), M6.9 Noto Hanto earthquake in 2007 (e.g. Ozawa et al 2008) and the M6.8 Niigataken Chuetsu-oki earthquake (e.g.…”

Section: Introductionmentioning

confidence: 99%

Strain accumulation process around the Atotsugawa fault system in the Niigata-Kobe Tectonic Zone, central Japan

Ohzono¹,

Sagiya²,

Hirahara³

et al. 2011

Geophysical Journal International

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S U M M A R YIn order to investigate the strain accumulation process around the Niigata-Kobe Tectonic Zone in central Japan, we estimate a precise GPS velocity field around a representative fault area, the Atotsugawa fault system. The velocity profiles obtained from two dense GPS arrays crossing the Atotsugawa fault demonstrate the existence of a laterally heterogeneous deformation pattern along the fault strike. The West Array suggests the possibility of surface fault creep, which disagrees with inferences gleaned from previous EDM measurements. High shear strain rate, which is calculated from wider velocity field, distributes around not only the Atotsugawa fault system, but also the Takayama-Oppara fault zone, which is located 50 km south from the Atotsugawa fault. In order to consider the effect of interaction between those active faults, we conduct a block-fault model analysis. Our block model consists of nine blocks and 33 fault segments. Relative motion between two blocks at the northern and southern ends of the fault system is calculated to be 9.9 mm yr −1 . The intervening region between these two blocks corresponds to the Niigata-Kobe Tectonic Zone with a strain rate of 0.2 ppm yr −1 . Slip deficit rates at the Atotsugawa, Ushikubi, and Takayama-Oppara fault zones are estimated to be 2.2, 3.9 and 2.3 mm yr −1 , respectively. Although the ratio of slip deficit rate (2.2 : 3.9 : 2.3 ≈ 1 : 2 : 1) of these three faults is similar to that of geological long-term slip rates (1 : 2 : 0.7), the magnitude of geodetic slip deficits is 30 per cent to 50 per cent larger than long-term slip rates. This systematic difference may be due to inelastic deformation of the crust in this region. Since the total slip deficit rate between the Ushikubi and the Takayama-Oppara fault zone is 8.4 mm yr −1 , about 85 per cent of the relative block motion, the deformation is mostly accommodated by elastic strain accumulation on these three faults.

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Coseismic deformation of the Mid Niigata prefecture Earthquake in 2004 detected by RADARSAT/InSAR

Cited by 19 publications

References 9 publications

Aftershock distribution of the 2004 Mid Niigata Prefecture Earthquake derived from a combined analysis of temporary online observations and permanent observations

Aftershock distribution of the 2004 Mid Niigata Prefecture Earthquake derived from a combined analysis of temporary online observations and permanent observations

Fault‐related folds above the source fault of the 2004 mid‐Niigata Prefecture earthquake, in a fold‐and‐thrust belt caused by basin inversion along the eastern margin of the Japan Sea

Strain accumulation process around the Atotsugawa fault system in the Niigata-Kobe Tectonic Zone, central Japan

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