中国科学D辑(英文版)
中國科學D輯(英文版)
중국과학D집(영문판)
SCIENCE IN CHINA(SCIENTIA SINICA)
2002年
6期
550-558
,共9页
张中杰%李英康%王光杰%滕吉文%S.Klemperer%李敬卫%范进义%陈赟
張中傑%李英康%王光傑%滕吉文%S.Klemperer%李敬衛%範進義%陳赟
장중걸%리영강%왕광걸%등길문%S.Klemperer%리경위%범진의%진빈
northern Tibet%wide-angle seismic profile%P- and S-wave velocity%Poisson's ratio%"down-bowing" Moho%eastward flow of materials
We recognized 6 sets of reflecting P- and S-wave events from Moho and other interfaces within the crust, respectively, with the wide-angle seismic data acquired from 510 km-long Selincuo-Ya'anduo profile in the northern Tibet, fitted the observed events with forward modeling, and interpreted crustal structure of P- and S-wave velocities and Poisson's ratio under the profile. The results demonstrate that the crustal structure between Yarlungzangbo and Bangong-Nujiang sutures changes abruptly, and the crust is the thickest at the middle part of the profile with thickness of 80 km or more. The "down-bowing" Moho is the striking feature for the crustal variation along the west-east direction. The Moho uplifts with steps, and the uplifting rate westward is greater than that eastward. The heterogeneity of P- and S-wave velocities exists both vertically and horizontally, and one lower velocity layer (LVL) exists with the depth range of 27-34 km and the thickness range of 5-7 km. For the upper crust, Poisson's ratio is the lowest at the middle part of the profile; for the lower crust, the Poisson's ratio at the east segment is lower than that at west segment, which means that the crustal rigidity for the upper crust is different from the lower crust, and the lower crust under the east segment of the profile is more ductile. We infer that the substance in the lower crust endured eastward flow along with the collision between Eurasian and Indian plates, and the "down-bowing" Moho is attributable to the multi-phase E-W tectonic processes.