Internal Structure and Permeability of Wenchuan Earthquake Fault

详细信息   

• 责任者：Chen Jianye (State Key Laboratory of Earthquake Dynamics ; Institute of Geology ; China Earthquake Administration ; Beijing 100029 ; China) ; Yang Xiaosong
• 刊名：Chinese Journal of Geophysics
• 出版年：2011
• 卷期：54(7)
• 关键词：汶川地震2008 ; Wenchuan earthquake 2008 ; 地震构造 ; seismotectonics ; 龙门山断裂带 ; Longmenshan Fault Zone
• 页码：p.1805-1816
• 图表：6 illus., 2 tables, 37 refs.
• 分类号：0500
• issnNo：ISSN0001-5733
• isbnNo：CN11-2074/P

摘要

Cross-fault permeability measurement was conducted on the Wenchuan earthquake fault. The results showed that this earthquake fault consists of fault core with low permeability （2. 4×10^-19 - 3. 8 × 10^16 m^2 ）, highly permeable damaged zone （3.7 × 10^16-3.0× 10-^15 m^2） and the fractured protolith （6.0 × 10^-18 - 4.3 × 10^-13 m^2） （40 MPa effective pressure）, among which fresh gouges on the main slip surface are the most impermeable. Impeded by the impermeable protolith and fault gouge, cross-fault fluid flow was inhibited and fluid activity was confined within the damaged zone. This recognition is consistent with microstructure and grain size distribution of fault rocks. Condition of co-seismic thermal pressurization was calculated and the results showed that at depth greater than 2 km, the main slip zone of Wenchuan earthquake has the characteristics of low permeability for thermal pressurization to occur.