摘要
为探究地震对断层带气体逸出的影响和震后气体地球化学特征随时间的变化,以及地震动力学特征,利用土壤气地球化学方法,于2010年4月14日青海玉树Ms7.1级地震断层甘达村段测量地表破裂特征和震后断层气氡和汞浓度,发现断层带土壤的气氡和汞浓度的平均值分别为9246 Bq/m3和4.2 ng/m3。破裂带中Rn浓度变化幅度大,而Hg的浓度变化较小。断层主滑面附近Rn浓度相对降低,为地表破裂后断层气逃逸所致。泉水气氡观测发现,震前氡浓度增高,表明地震断层活动性增强。因此巴颜喀拉地块向东不均匀挤压,使深部气体沿地震断裂逃逸至地表,这也是造成断层带气氡、汞浓度的增高的原因。
To understand the earthquake fault geodynamic characteristics and the relationship between seismic activity and fault gas,soil gas geochemistry methods were used to investigate the surface rupture and the concentrations of Rn and Hg in the fault zone,which is a co-seismic fault of Yushu Ms 7.1 earthquake,April 14th,2010,nearby the Ganda village,Yushu.The average concentrations of Rn and Hg in soils collected nearby the Ganda village fault zone were 9246 Bq/m3 and 4.2 ng/m3,respectively.Soil gas escaping after the surface rupture generated a low concentration of Rn around the major slip plane of the fault.The concentration increasing of Rn in spring before Yushu earthquake indicated increasing of fault activities.The heterogeneously extruding of Bayankela plate from west caused the left-lateral slip of the Ganzi-Yushu fault.The deep gas escaped to the surface during earthquake rupture resulted in concentration increasing of Ra and Hg in the fault zone.
出处
《矿物岩石地球化学通报》
CAS
CSCD
北大核心
2011年第2期129-134,共6页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
中国地震局地震预测研究所玉树地震应急考察项目
基本科研业务费项目(02092436)
