中-意-法阿尔卑斯地震探测：深部构造与碰撞造山带动力学

The project CIFALPS (China-Italy-France Alps Seismic Survey ) will carry out seismic survey across the Western Alps through international cooperation with French and Italian geoscientists. It is proposed to install a 350-km-long dense (station spacing of 5 to 10 km) seismic profile across the Southwestern Alps, with offline stations being installed on both sides of the main line to improve the 2-D coverage of the area. Through the seismic survey, we will 1) image the crustal structure of the Southwestern Alps with a high-resolution, and address the deep geometry of the Frontal Penninic Thrust; 2) image the mantle structure of the Southwestern Alps, and address the geometry of the subduction beneath the Western Po plain and mantle flow pattern beneath the Western part of the Alpine orogen. With this data (resolution of <10 km in the crust and <50 km in the mantle), we will better understand the part played by mantle dynamics in the past and present evolution of the mountain range and the geomorphology of the significant part of Western Europe affected by the Alpine orogeny.

本项目将通过中国-法国-意大利三方国际合作，以1 条密集台站剖面（长约350 公里，台间距5-10 公里）加设2 条辅助剖面的面状展布形式布设流动宽频带地震台阵，对西阿尔卑斯山进行深部构造观测，获得观测廊带下方地壳—上地幔的高分辨率地震结构图像、上地幔变形特征信息（地壳横向分辨率小于10km；岩石圈深度横向分辨率小于50km）。通过流动地震台阵观测，我们将：1）获得西阿尔卑斯山地壳结构的高分辨率结构成像，揭示平宁构造带逆冲前缘在深部的构造几何学形态；2）获得西阿尔卑斯山地区岩石圈及上地幔三维结构图像及上地幔变形信息，揭示波河平原下俯冲带的精细几何学形态和俯冲板块的性质。通过研究区域地壳内部、壳幔过渡带和上地幔不同圈层的物性状态和结构横向变化特征，深入认识阿尔卑斯造山带的动力学过程与机制及其对西欧现代地貌的重大影响。

项目已完成全部计划研究内容。. 由岩石圈演化国家重点实验室和国家自然科学基金委共同资助，完成“中-意-法阿尔卑斯地震探测”总计55个宽频带流动台站的布设任务；获得西阿尔卑斯地区观测廊带下方高分辨率地壳结构图像，首次获得了欧洲地壳深俯冲至75公里之下的地震学证据；获得西阿尔卑斯地区高分辨率上地幔速度结构图像及变形特征。开展了国际合作研究和学术交流，组织召开了“阿尔卑斯－安纳托利亚－伊朗深部结构新观测”国际研讨会。