地质学报（英文版）2009，Vol.83Issue(4)：746-753,8.
Preliminary Results of In-situ Stress Measurements along the Longmenshan Fault Zone after the Wenchuan Ms 8.0 Earthquake
Preliminary Results of In-situ Stress Measurements along the Longmenshan Fault Zone after the Wenchuan Ms 8.0 Earthquake
摘要
Abstract
Four months after the Wenchuan Ms 8 earthquake in western Sichuan, China, in situ stress measurements were carried out along the Longmenshan fault zone with the purpose of obtaining stress parameters for earthquake hazard assessment. In-situ stresses were measured in three new boreholes by using overcoring with the piezomagnetic stress gauges for shallow depths and hydraulic fracturing for lower depths. The maximum horizontal stress in shallow depths (～20 m) is about 4.3 MPa, oriented NI9°E, in the epicenter area at Yingxiu Town, about 9.7 MPa, oriented N51°W, at Baoxing County in the southwestern Longmenshan range, and about 2.6 MPa, oriented N39°E, near Kangding in the southernmost zone of the Longmenshan range. Hydraulic fracturing at borehole depths from 100 to 400 m shows a tendency towards increasing stress with depth. A comparison with the results measured before the Wenchuan earthquake along the Longmenshan zone and in the Tibetan Plateau demonstrates that the stress level remains relatively high in the southwestern segment of the Longmenshan range, and is still moderate in the epicenter zone. These results provide a key appraisal for future assessment of earthquake hazards of the Longmenshan fault zone and the aftershock occurrences of the Wenchuan earthquake.关键词
Wenchuan Ms 8.0 earthquake, in-situ stress measurement, overcoring, hydraulic fracturing, Longmenshan fault beltKey words
Wenchuan Ms 8.0 earthquake, in-situ stress measurement, overcoring, hydraulic fracturing, Longmenshan fault belt分类
天文与地球科学引用本文复制引用
WU Manlu,ZHANG Yueqiao,LIAO Chunting,CHEN Qunce,MA Yinsheng,WU Jinsheng,YAN Junfeng,OU Mingyi..Preliminary Results of In-situ Stress Measurements along the Longmenshan Fault Zone after the Wenchuan Ms 8.0 Earthquake[J].地质学报（英文版）,2009,83(4):746-753,8.基金项目
This study was conducted under the auspice of National Key Basic Project (973) (granted No. 2008CB425702) and National Science and Technology Project (granted No. SinoProbe-06). （973）
