<i>Pn</i>Velocities Beneath Continental Collision Zones: the Turkish-Iranian Plateau

Hearn, Thomas M.; Ni, James

doi:10.1111/j.1365-246x.1994.tb03931.x

Cited by 196 publications

(171 citation statements)

References 35 publications

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“…These low-velocity anomalies are associated with volcanic activity, i.e., the Tengchong volcano, and is likely a result of the higher temperatures and/or partial melting associated with volcanism (Hearn and Ni, 1994). Low P n velocity anomalies are also associated with the subduction in the Hindu Kush region as well.…”

Section: Resultsmentioning

confidence: 99%

P n tomographic velocity and anisotropy beneath the Tibetan Plateau and the adjacent regions

Liu

et al. 2011

Earth Planet Sp

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We present a tomographic velocity and anisotropy model of the uppermost mantle beneath the Tibetan Plateau and the adjacent regions. The investigation analyzed 105,385 P n phase readings from the International Seismological Centre (ISC) and the China Earthquake Data Center. The average P n velocity under the study area is approximately 8.15 km/s, with velocity perturbations up to 3-4%. We find high P n velocities under the Indian Plate and in the Tarim and Sichuan basins, low P n velocities under the Hindu Kush and in Myanmar and the adjacent region, and especially low P n velocities under the area north of the Indus-Yarlung Zangbo suture. The high P n velocity anomalies of the Indian Plate are discontinuous at the collision region in the east-west direction, indicating that the Indian Plate probably subducts in a piecewise manner. Distributions of P n velocities are used to validate mechanisms for the subduction of the Indian Plate presented in previous studies. In addition, P n anisotropy is obtained simultaneously with P n velocity. At plate collision zones, the fast P n anisotropy direction is parallel to the direction of the collision edge. We validate the existence of P n anisotropy under these regions and discuss the relationship of anisotropy with tectonic structure and plate movement.

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Section: Resultsmentioning

confidence: 99%

P n tomographic velocity and anisotropy beneath the Tibetan Plateau and the adjacent regions

Liu

et al. 2011

Earth Planet Sp

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“…Following Hearn's approach and computation method (Hearn and Ni, 1994;Hearn, 1996), we invert travel-time difference residuals between Pn and Sn for lateral velocity variation of the pseudowave within the mantle lid. Equation (3) can be recast as Ax d, where d is the data vector, x is the vector of unknowns, and A represents the model parameters.…”

Section: Methodsmentioning

confidence: 99%

Imaging Poisson's Ratio of the Uppermost Mantle beneath China

Shi

Sun

et al. 2011

Bulletin of the Seismological Society of America

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(1) the pseudowave velocity is high and the velocity ratio (V P =V S ) and Poisson's ratio are low in the stable cratons around the Tibetan Plateau such as the Tarim and Junggar basins, the Ordos craton, and the southern region of the Sichuan basin; (2) a low pseudowave velocity and high velocity ratio and Poisson's ratio exist in the central and northern Tibetan Plateau, the North-South Seismic Zone, and north China; and (3) the high velocity ratio and Poisson's ratio region in the Tibetan Plateau extends to the surrounding cratons, suggesting that the uplift of the Tibetan Plateau results from a high Poisson's ratio or partially melted rocks beneath the plateau and that the softer rocks have intruded into the upper mantle of surrounding cratons.

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“…[30] Checkerboard tests are commonly used to assess model resolution in tomographic studies [e.g., Hearn and Ni, 1994;Zelt and Barton, 1998]. Although the details of individual tests may vary, they all follow similar principles.…”

Section: Traveltime Fitting and Resolutionmentioning

confidence: 99%

Seismological evidence for variable growth of crust along the Izu intraoceanic arc

Kodaira¹,

Sato²,

Takahashi³

et al. 2007

J. Geophys. Res.

145

209

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[1] The processes that create continental crust in an intraoceanic arc setting are a matter of debate. To address this issue, we conducted an active source wide-angle seismic study to examine along-arc structural variations of the Izu intraoceanic arc. The data used were acquired over a 550-km-long profile along the volcanic front from Sagami Bay to Tori-shima. The obtained structural model showed the existence of felsic to intermediate composition middle crust with a P wave velocity (Vp) of 6.0-6.5 km s À1 in its upper part and 6.5-6.8 km s À1 in its lower part. The thickness of the middle crust varied markedly from 3 to 13 km. The underlying lower crust also consisted of two layers (Vp of 6.8-7.2 km s À1 in the upper part and Vp of 7.2-7.6 km s À1 in the lower part). The upper of these layers was interpreted to consist of plutonic gabbro, and the lower layer was interpreted to be mafic to ultramafic cumulates. Average crustal velocities calculated from our model showed remarkable lateral variation, which correlated well with arc volcanism. Low average crustal seismic velocities ($6.7 km s À1

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PnVelocities Beneath Continental Collision Zones: the Turkish-Iranian Plateau

Cited by 196 publications

References 35 publications

P n tomographic velocity and anisotropy beneath the Tibetan Plateau and the adjacent regions

P n tomographic velocity and anisotropy beneath the Tibetan Plateau and the adjacent regions

Imaging Poisson's Ratio of the Uppermost Mantle beneath China

Seismological evidence for variable growth of crust along the Izu intraoceanic arc

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