Strain and rotation rate from GPS in Tibet, Anatolia, and the Altiplano

Allmendinger, Richard W.; Reilinger, Robert; Loveless, John P.

doi:10.1029/2006tc002030

Cited by 158 publications

(136 citation statements)

References 74 publications

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“…They suggested that the strain rate fields determined by geodetic measurements taken on a decadal timescale are consistent with geological observations on a 10 4 years timescale. Allmendinger et al [66] derived 2-D strain and rotation rate fields from a GPS velocity field using both the nearest neighbor and distance weighted approach. Their results showed that the principal infinitesimal strain rate axes in Tibet are consistent with large, long term geological structures similar to England and Molnar [2].…”

Section: Discussionmentioning

confidence: 99%

Interseismic Deformation of the Altyn Tagh Fault Determined by Interferometric Synthetic Aperture Radar (InSAR) Measurements

Zhu

Wen

et al. 2016

Remote Sensing

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Abstract:The Altyn Tagh Fault (ATF) is one of the major left-lateral strike-slip faults in the northeastern area of the Tibetan Plateau. In this study, the interseismic deformation across the ATF at 85˝E was measured using 216 interferograms from 33 ENVISAT advanced synthetic aperture radar images on a descending track acquired from 2003 to 2010, and 66 interferograms from 15 advanced synthetic aperture radar images on an ascending track acquired from 2005 to 2010. To retrieve the pattern of interseismic strain accumulation, a global atmospheric model (ERA-Interim) provided by the European Center for Medium Range Weather Forecast and a global network orbital correction approach were applied to remove atmospheric effects and the long-wavelength orbital errors in the interferograms. Then, the interferometric synthetic aperture radar (InSAR) time series with atmospheric estimation model was used to obtain a deformation rate map for the ATF. Based on the InSAR velocity map, the regional strain rates field was calculated for the first time using the multi-scale wavelet method. The strain accumulation is strongly focused on the ATF with the maximum strain rate of 12.4ˆ10´8/year. We also show that high-resolution 2-D strain rates field can be calculated from InSAR alone, even without GPS data. Using a simple half-space elastic screw dislocation model, the slip-rate and locking depth were estimated with both ascending and descending surface velocity measurements. The joint inversion results are consistent with a left-lateral slip rate of 8.0˘0.7 mm/year on the ATF and a locking depth of 14.5˘3 km, which is in agreement with previous results from GPS surveys and ERS InSAR results. Our results support the dynamic models of Asian deformation requiring low fault slip rate.

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Section: Discussionmentioning

confidence: 99%

Interseismic Deformation of the Altyn Tagh Fault Determined by Interferometric Synthetic Aperture Radar (InSAR) Measurements

Zhu

Wen

et al. 2016

Remote Sensing

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“…We calculated a smooth and continuous strain rate field for the Tibetan Plateau and surroundings from combined GPS data, which is similar to results of Allmendinger et al [2007], England and Molnar [2005], and Gan et al [2007], by employing an updated code for interpolation of strain rate [Shen et al, 2015]. At a given site, the horizontal velocity field in its vicinity was approximated by a bilinear function and represented by translation, rotation, and strain rates.…”

Section: 1002/2015gl064347mentioning

confidence: 99%

Present‐day crustal thinning in the southern and northern Tibetan Plateau revealed by GPS measurements

Molnár

Shen

et al. 2015

Geophysical Research Letters

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GPS measurements from sites within the Tibetan Plateau show not only east‐southeast‐west‐northwest extension but also, more importantly, horizontal dilation throughout the interior of the plateau. Assuming conservation of volume, vertical (thinning) strain rates equal horizontal dilation rates, and they, 8.9 ± 0.8 nanostrain a−1 and 7.4 ± 1.2 nanostrain a−1 in northern and southern Tibet, and 12.0 ± 3.2 nanostrain a−1 in its southwestern part, suggest no measureable difference. Principal extensional strain rates also are similar in magnitude and orientation. If crustal thinning began at 10–15 Ma and the current rates of horizontal dilation applied both to the entire crust and to that period, the crust should have thinned by 5.5–8.5 km. If isostatic equilibrium applied, the mean elevation of the plateau would have dropped ~1 km. The similar rates for northern, southern, and southwestern Tibet suggest that the processes dictating crustal extension, normal faulting, and crustal thinning in the three regions differ little from one another.

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“…where indexes i and j correspond to spatial coordinates, t i is the velocity with respect to the grid point, e ij is the velocity gradient tensor, u i is the individual GPS velocities, and Dx j is the baseline between each station and the grid point (Shen et al 1996;Allmendinger et al 2007;Crowell et al 2013). The following inverse problem is set up to solve for the velocity gradient tensor ¼ Gl …”

Section: Strain Rate Computationmentioning

confidence: 99%

Heterogeneous strain regime in the eastern margin of Tibetan Plateau and its tectonic implications

Meng

et al. 2015

Earthq Sci

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The eastern margin of Tibetan Plateau is one of the most active zones of tectonic deformation and seismicity in China. To monitor strain buildup and benefit seismic risk assessment, we constructed 14 survey-mode global position system (GPS) stations throughout the northwest of Longmenshan fault. A new GPS field over 1999-2011 is derived from measurements of the newly built and pre-existing stations in this region. Sequentially, two strain rate fields, one preceding and the other following the 2008 M W 7.9 Wenchuan earthquake, are obtained using the Gausian weighting approach. Strain field over 1999-2007 shows distinct strain partitioning prior to the 2008 M W 7.9 Wenchuan earthquake, with compression spreading over around Longmenshan area. Strain field derived from the two measurements in 2009 and 2011 shows that the area around Longmenshan continues to be under striking compression, as the pattern preceding the Wenchuan earthquake, implying a causative factor of the sequent of 2013 M W 6.7 Lushan earthquake. Our GPSderived dilatation shows that both the Wenchuan and Lushan earthquakes occurred within the domain of pronounced contraction. The GPS velocities demonstrate that the Longriba fault underwent slight motion with the faultnormal and -parallel rates at 1.0 ± 2.5 mm and 0.3 ± 2.2 mm/a; the Longmenshan fault displayed slow activity, with a fault-normal rate at 0.8 ± 2.5 mm/a, and a fault-parallel rate at 1.8 ± 1.7 mm/a. Longriba fault is on a par with Longmenshan fault in strain partitioning to accommodate the southeastward motion of eastern margin of the Tibetan Plateau. Integrated analysis of principal strain tensors, mean principal stress, and fast directions of mantle anisotropy shows that west of Sichuan is characterized as mechanically strong crust-mantle coupling.

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Strain and rotation rate from GPS in Tibet, Anatolia, and the Altiplano

Cited by 158 publications

References 74 publications

Interseismic Deformation of the Altyn Tagh Fault Determined by Interferometric Synthetic Aperture Radar (InSAR) Measurements

Interseismic Deformation of the Altyn Tagh Fault Determined by Interferometric Synthetic Aperture Radar (InSAR) Measurements

Present‐day crustal thinning in the southern and northern Tibetan Plateau revealed by GPS measurements

Heterogeneous strain regime in the eastern margin of Tibetan Plateau and its tectonic implications

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