EAPSI: Characterizing the Structural Evolution of the Longmen Shan Fault Zone in Eastern Tibet

2008年5月12日，靠近青藏高原东部边缘的中国四川龙门山地区发生里氏7.9级地震。地震造成大量人员伤亡，并对地区基础设施造成广泛破坏。尽管经过了几十年的研究，这个地震活跃地区的构造历史仍然知之甚少。该项目由PI C. Gabriel Creason负责，旨在通过更好地约束龙门山断裂带主要断层的运动，提高我们对龙门山断裂带地质演化的认识。该项目将由项目负责人和中国科学院地质与地球物理研究所高级研究员、西藏地质领域著名科学家王尔哲博士共同努力。此次合作的目的有两个：1)构建地质剖面，以完善龙门山区域地质解释；2)在为期两周的野外活动中，解释该地区的当地地层和构造地质。此外，该项目还将作为加强研究小组之间正在进行的国际合作的背景。了解龙门山地区何时以及如何达到其现代高海拔（5000米）是构造地貌学（例如，表征青藏高原对印度大陆北侵的地形和结构反应）和地震学（例如，评估活跃构造地区的地震危险性）领域更广泛问题的基础。因此，本研究的首要目标是重建龙门山内彭关、碧川和汶川断裂新生代断层滑动的震级和运动学。为了更好地阐明该地区的构造地层格架，将构建几个地质剖面来展示这些断层的构造地层格架。新生代演化。在野外工作期间收集的数据将用于测试新生代沉积物沉积与山脉前缘西部挖掘之间的相关性，并随后评估断层运动、挖掘和沉积沉积之间联系的可能性。该奖项隶属于东亚和太平洋暑期研究所项目，由美国国家科学基金会和中国科技部共同资助，支持美国研究生的暑期研究。

On May 12, 2008, a Mw 7.9 earthquake devastated the Longmen Shan region of Sichuan, China, near the eastern margin of the Tibetan Plateau. The earthquake resulted in numerous casualties and extensive damage to the regional infrastructure. Despite decades of research, the tectonic history of this seismically active region remains poorly understood. This project, by PI C. Gabriel Creason, seeks to improve our understanding of the geologic evolution of the Longmen Shan fault zone by better constraining the movement of its major faults. The project will be a joint effort between the PI and host researcher Dr. Erchie Wang, a Senior Researcher at the Institute of Geology and Geophysics, Chinese Academy of Sciences, and renowned scientist in the field of Tibetan geology. The objectives of this collaborative effort are two-fold: 1) construct geologic-cross sections in order to refine interpretations of regional geology of the Longmen Shan; and 2) during a two-week field campaign, interpret the local stratigraphy and structural geology of the area. Additionally, the project will also serve as a backdrop to strengthen ongoing international collaboration between research groups.Understanding when and how the Longmen Shan region reached its high modern elevation (5000 m) are intrinsic questions that underlie broader questions in the fields of tectonic geomorphology (e.g., characterizing the topographic and structural response of the Tibetan Plateau to the northward incursion of the Indian continent) and seismology (e.g., assessing seismic hazard in regions with active tectonics). Thus, the overarching goal of this research is to reconstruct the magnitude and kinematics of Cenozoic fault slip along the Pengguan, Biechuan and Wenchuan faults located within the Longmen Shan. Several geologic cross-sections demonstrating the tectonostratigraphic framework of these faults will be constructed with the collective aim to better elucidate the region?s Cenozoic evolution. Data collected during fieldwork will be used to test for correlations between Cenozoic deposition of sediments and exhumation of the range-front to the west, and, subsequently, to assess the possibility of a linkage between fault motion, exhumation, and sedimentary deposition.This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the Ministry of Science and Technology of China.