汶川8.0级地震前地下流体长趋势变化特征讨论  

Discussion on the Long-time Trend Change Characteristics of Subsurface Fluid before the Wenchuan MS8.0 Earthquake

作　　者：陆明勇[1] 房宗绯[1] 赵丽葵[1] 

机构地区：[1]中国地震应急搜救中心,北京100049

出　　处：《地震》2010年第1期61-72,共12页Earthquake

基　　金："十一五"国家科技支撑项目(2006BAC01B02-03-04;2006BAC01B02-02-01)

摘　　要：通过对汶川MS8.0地震震中周围地区震前地下流体长期观测资料的分析表明,震前地下流体出现了长趋势变化,其特征是时间早、范围广,具有协调性以及向未来震中迁移等特征,形态主要为趋势转折、破年变、加速等,其中大多数为趋势转折变化。进一步对比研究地壳形变、地下流体长趋势变化发现,地壳形变和地下流体长趋势变化迁移特征一致,地壳形变长趋势时间较早于地下流体长趋势变化时间,形变出现张压变化与水位变化有比较密切的关系,即形变大部分出现缓慢压性变化或张性减缓变化,水位大部分出现缓慢上升或下降减缓变化。最后讨论了地下流体长趋势变化机理。Long-time observed data of Subsurface fluid from a wide circumferential region of the Wenchuan Ms8. 0 epicenter is analyzed before the earthquake. The result show that the subsurface fluids have long-time trend changes before the Wenchuan Ms8. 0 earthquake. The changes are characterized by earlier emerging time, wider range, compatibility and migration toward the epicenter etc. The shape of subsurface fluid long-time trend change is characterized by trend turn, annual variation damage and accelerating variation etc, mostly trend turns. Further comparative study with crustal deformation shows that the long-time trend change migration of subsurface fluid and crustal deformation is identical, and the long-time trend change time of crustal deformation is earlier than that of subsurface fluid. The tensor-pressure variation of crustal deformation is more closely related with the level variation of underground water, namely if the long-time trend change of crustal deformation is the majority variation shape of slow pressure or tensor diminution, then the long-time trend change shape of of underground water level is the majority variation shape of slow elevation or descending diminution. Finally, the productive mechanism on long-time trend change of subsurface fluid is discussed before Wenehuan Ms8.0 earthquake .

关 键 词：地下流体 地壳形变 汶川MS8.0级地震 长趋势变化机理 

分 类 号：P315.72[天文地球—地震学]