Acquisition Method Study of 2D Reflection Seismic Short Profile Through WFSD-1 in Main Faults of Wenchuan Earthquake
详细信息
- 责任者：Chen Qiang (Geophsics and Information Technology Institute ; CUG ; Beijing 100083 ; China) ; Qian Rongyi
- 刊名：Chinese Journal of Geophysics
- 出版年：2011
- 卷期：54(8)
- 关键词：反射波法 ; reflection methods ; 数据采集 ; data acquisition ; 四川 ; Sichuan Province
- 页码：p.2060-2071
- 图表：7 illus., 27 refs.
- 分类号：1600
- issnNo：ISSN0001-5733
- isbnNo：CN11-2074/P
摘要
The serial reflection seismic profiles investigation across the Longmen Mountain is an important project in Wenchuan Earthquake Fault Zone Scientific Drilling （WFSD）. The 2D artificial reflection seismic experiment in Scientific Drilling Site of WFSD-1 Pilot hole completedthe prescribed task, including： （1） Successfully obtained the first 2D reflection profile of WFSD in extreme adverse environments with steep terrain, developing ruptures, fracture, slumped bodies and bad weather, right after the 5 - 12 Wenchuan earthquake; （2） Based on the study of the complex structure condition in Middle Longmenshan Fore-mountain area, seismic data acquisition methods featuring high spatial and time sampling density were proposed for detecting the complex geological reflective bodies in the shallow, middle and deep part of the area, providing the basic idea and acquisition parameters for the next observations; （3） It is the first of such studies to find multi-level geological body reflectors in the western part （5 km） to the exposed location of Yingxiu-Beichuang faults. The middle and deep reflection body below 1.2 s show obvious layer formation of sediment or metamorphosed rocks. It is estimated that the maximum thickness of Penguan Complex is about 3 kin. （4） The Guanxian-Anxian faults area shows clear double-layer reflection structure. The concealed piedmont zone has complete sediment system. （5） Employing dense observation method with 20-30 m shot and 10m receiver spacing within 800 m of WFSD-1, the study acquired reliable raw data for highly-accurate calibration to reflectors within the depth of WFSD-1.