Modeling the rupture process of the 2003 September 25 Tokachi‐Oki (Hokkaido) earthquake using 1‐Hz GPS data

Miyazaki, S.; Larson, Kristine M.; Choi, Kyu-Hong; Hikima, Kazuhito; Koketsu, Kazuki; Bodin, Paul; Haase, Jennifer S.; Emore, G.; Yamagiwa, Atsushi

doi:10.1029/2004gl021457

Cited by 117 publications

(75 citation statements)

References 23 publications

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“…Hence, in order to estimate more accurate distributions of the subsurface dislocations, it is important to use the GF's calculated with realistic subsurface structures with adequate material properties such as the Young's modulus and Poisson's ratio, instead of those for the homogeneous elastic half space mostly used so far. For instance, as mentioned in the first section, there have already been some inversion studies in which the distribution of coseismic slip or afterslip associated with the 2003 Tokachi-oki (Hokkaido, northeastern Japan) earthquake (M 8.0) was derived from the displacements at many sites of GEONET in Hokkaido and northern Tohoku which are the same regions as those modeled in this work (e.g., Miyazaki et al, 2004aMiyazaki et al, , 2004bMiura et al, 2004;Ozawa et al, 2004) or from the landbased GEONET data together with those by ocean-bottom pressure gauges (Baba et al, 2006). However, most of these studies used the GF's for the surface displacements calculated with the assumptions of homogeneous elastic half space.…”

Section: Discussionmentioning

confidence: 77%

Effect of elastic inhomogeneity on the surface displacements in the northeastern Japan: Based on three-dimensional numerical modeling

et al. 2007

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In geodetic inversions such as estimation of coseismic slip and/or afterslip distribution on faults, the displacements on the surface calculated under an assumption of homogeneous elastic half space have been mostly used as the Green's functions (GF's). However, this seems not adequate for better estimations of such slip distribution, because the subsurface structures are more or less inhomogeneous, especially those in and around Japan where the structure must be much complicated. In this study, to examine how much the inhomogeneous subsurface structure affects on the surface displacements, we conduct some 3-D finite element calculations with a grid for the region of 1400 km (EW) × 1200 km (NS) × 200 km (depth) including the Tohoku and Hokkaido, northeastern Japan. Assuming homogeneous and inhomogeneous elastic models with various values for the Young's modulus and Poisson's ratio, we calculated the surface displacements due to a dip-slip type dislocation of 1 m on many cell-like subfaults assumed on the interface between the Pacific and land side plates. Comparing the results, we find a large discrepancy in the surface displacements between the homogeneous and inhomogeneous elastic models and less dependency of the surface displacements on the Poisson's ratio. The discrepancy is found to be more than 20% and can be as large as ∼40% in some cases. Such a large discrepancy indicates that the surface displacements calculated for inhomogeneous elastic medium with realistic subsurface structure, unlike as in usual cases, should be used as the GF's for better geodetic inversions.

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Section: Discussionmentioning

confidence: 77%

Effect of elastic inhomogeneity on the surface displacements in the northeastern Japan: Based on three-dimensional numerical modeling

et al. 2007

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“…Broadband seismometers, however, are not sensitive enough to detect these ultra-long-period slow slips. Larson et al (2003) found good agreement between strong ground-motion records integrated to displacement and 1-Hz Global Positioning System (GPS) position estimates collected more than several hundred kilometers from the 2002 Denali earthquake epicenter. They also suggested that such observations are key for studying the rupture directivity and dynamic earthquake source processes.…”

Section: Introductionmentioning

confidence: 79%

“…They also suggested that such observations are key for studying the rupture directivity and dynamic earthquake source processes. Miyazaki et al (2004) investigated rupture process of 2003 Tokachi-Oki (Hokkaido) earthquake based on high-date kinematic GPS results. They suggested that high-rate GPS is more sensitive to cumulative slip distribution.…”

Section: Introductionmentioning

confidence: 99%

Large surface wave of the 2004 Sumatra-Andaman earthquake captured by the very long baseline kinematic analysis of 1-Hz GPS data

et al. 2006

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The 26 December 2004 Sumatra-Andaman great earthquake had a −1500 km long rupture of more than 600 seconds duration, and may have involved a complex rupture process including slow slip. We processed International GNSS Service (IGS) 1-Hz Global Positioning System (GPS) data using kinematic analysis to investigate ground motion caused by this large earthquake. Since there are few 1-Hz stations, we had to process long baseline up to several thousand kilometers long. Long baselines degrade the GPS carrier phase ambiguity resolution. Nevertheless, clear seismic surface waves of the earthquake are recorded in our longdistance kinematic GPS solutions, which are in good agreement with response-corrected broadband seismic record. Our long baseline kinematic GPS solutions clearly indicated directivity of the seismic wave associated by rupture process of this earthquake. Also at the GPS stations that are 2,000 km away from the epicenter, dynamic displacements exceeding 5-10 cm were detected. In contrast, short baseline kinematic analysis shows large strain change caused by passage of surface wave, which reaches 6 × 10 −6 . Based on the comparison with seismometer and spectrum analysis of GPS results, it is difficult to discuss for very long time period displacement such as with a period more than 600 seconds in this study.

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“…For this reason, white noise position estimation has been used extensively to measure seismic waves, e.g. Larson et al (2003) and Miyazaki et al (2004b). Unfortunately, the trade-off one makes by using white noise estimation is that very large geometric/multipath signals are still present in the time series.…”

Section: Kalman Filteringmentioning

confidence: 99%

Resolving static offsets from high-rate GPS data: the 2003 Tokachi-oki earthquake

Larson

Miyazaki

2008

Earth Planet Sp

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The M w 8.0 2003 Tokachi-oki earthquake offshore Hokkaido is the largest earthquake observed to date by a dense GPS network (GEONET). These GPS data are important both for resolving the geodetic signature of the earthquake itself and studies of postseismic deformation. Because GPS positions are generally estimated by averaging 24 hours of observations, it can be difficult to separate the effects of the earthquake and early postseismic deformation. In order to address this difficulty, a Kalman filtering methodology is developed that allows the estimation of the static offsets for the mainshock, its largest aftershock, and postseismic deformation in the first 24 hours. The static offsets computed for this study can be used for earthquake rupture studies while the early postseismic data can be used to evaluate frictional properties of the fault.

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Modeling the rupture process of the 2003 September 25 Tokachi‐Oki (Hokkaido) earthquake using 1‐Hz GPS data

Cited by 117 publications

References 23 publications

Effect of elastic inhomogeneity on the surface displacements in the northeastern Japan: Based on three-dimensional numerical modeling

Effect of elastic inhomogeneity on the surface displacements in the northeastern Japan: Based on three-dimensional numerical modeling

Large surface wave of the 2004 Sumatra-Andaman earthquake captured by the very long baseline kinematic analysis of 1-Hz GPS data

Resolving static offsets from high-rate GPS data: the 2003 Tokachi-oki earthquake

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