气候变化领域集成服务门户(CCPortal): Pn Tomographic Velocity and Anisotropy beneath the Iran Region

CCPortal

DOI	10.1785/0120100141
	Pn Tomographic Velocity and Anisotropy beneath the Iran Region
	Lu, Yan; Liu, Bin; Pei, Shunping; Sun, Youshun; Toksoez, M. Nafi; Zeng, Xiangfang
通讯作者	Lu, Y (通讯作者)
发表日期	2012
ISSN	0037-1106
EISSN	1943-3573
起始页码	426
结束页码	435
卷号	102 期号:1
英文摘要	We present tomographic velocity and anisotropy models of the uppermost mantle beneath the Iran region. A total of 74,375 Pn phase readings from 86 stations of the Iranian network and 133 stations of the International Seismological Centre are used in the investigation. The study uses the Pn travel-time tomography method proposed by Hearn (1996). The tomography results show some interesting anomalies. The average Pn velocity under the Iran region is approximately 8.0 km/s, and the maximum velocity perturbations are approximately 3%-4%. High Pn velocities under the Zagros Mountains and the Caspian Sea may be due to the presence of oceanic crust/lithosphere material. Low Pn velocities were found under the Alborz and Caucasus regions and may be due to higher temperatures or partial melting resulting from volcanoes and mid-Cenozoic volcanic/plutonic rocks in these regions. The inversion velocities support the idea that the subduction of the Arabian plate into the mantle beneath the Iranian plateau may have resulted in the upwelling of hot material. The well-resolved Pn anisotropy model is jointly obtained with a velocity model for the areas with good ray-path coverage. In the plate collision regions (Zagros and Alborz), the fast Pn anisotropy direction is oriented parallel to the collision arc and to large reverse faults due to pure shear deformation from cross-fault compression and along-fault extension. Under the Caucasus regions, the Pn anisotropy results indicate that the preferred alignment of olivine crystals is parallel to the plate movement direction; however, the surface fault strike is at an angle of nearly 45 degrees with the crustal movement direction and anisotropy. These differing deformations suggest potential decoupling between the crust and upper mantle. The possible decoupling and differing deformation between the crust and upper mantle are easily enhanced under high temperatures due to volcanoes and supported by low velocities beneath the Caucasus. We validate the existence of Pn anisotropy under these regions by azimuthal averaging of the apparent Pn velocity.
关键词	SURROUNDING REGIONS PLATEAU WAVE DEFORMATION EVOLUTION TURKEY PROPAGATION GEOLOGY TETHYS CHINA
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000300614700031
来源期刊	BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/258032
推荐引用方式 GB/T 7714	Lu, Yan,Liu, Bin,Pei, Shunping,et al. Pn Tomographic Velocity and Anisotropy beneath the Iran Region[J]. 中国科学院青藏高原研究所,2012,102(1).
APA	Lu, Yan,Liu, Bin,Pei, Shunping,Sun, Youshun,Toksoez, M. Nafi,&Zeng, Xiangfang.(2012).Pn Tomographic Velocity and Anisotropy beneath the Iran Region.BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA,102(1).
MLA	Lu, Yan,et al."Pn Tomographic Velocity and Anisotropy beneath the Iran Region".BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA 102.1(2012).