• 责任者：Li Shaohua (Department of Geophysics ; School of Earth and Space Sciences ; Peking University ; Beijing 100871 ; China) ; Wang Yanbin
• 刊名：Chinese Journal of Geophysics
• 出版年：2012
• 卷期：55(4)
• 关键词：地壳 ; crust ; 速度结构 ; velocity structure ; 甘肃 ; Gansu Province
• 页码：p.1186-1197
• 图表：5 illus., 3 tables, 40 refs.
• 分类号：0400
• issnNo：ISSN0001-5733
• isbnNo：CN11-2074/P

In this paper, the authors applied three-component full-waveform inversion combining niching genetic algorithm and reflectivity method to the southeastern Gansu and obtained average crustal structure for two regions. The western and eastern regions are located at the northeastern margin of Qinghai-Tibetan Plateau and its transition zone to the Ordos block. The waveform data was recorded by 24 broadband permanent seismic stations implemented in 2007 from an aftershock of Wenchuan earthquake occurred on August 1, 2008.The final average models show that the western and eastern region has similar P-wave velocity in the upper and lower crust, which are composed of felsic and intermediate materials. The P-wave velocity is 6.96 and 6.41 km/s, and the thickness is 19.8 and 9.3 km at the lower crust for the western and eastern region, respectively. The total crustal thickness is 54.6 and 47.9 km for the western and eastern region. These results imply that the lower crust is composed of mafic in the western region and intermediate material in the eastern region, and support that the crust thickening in the Qinghai-Tibetan block in the study region mainly occurred in the lower crust. The P-wave velocity for the upper mantle is 7.73 km/s at the western and 8.05 km/s at the eastern region, which corresponds to the young active tectonic region and old stable block, respectively. A sedimentary layer of 6.5 km thick is found at the eastern region with P-wave velocity of 5.78 km/s, but it is absent at the western region.