渭河盆地断裂活动速率的粒子群算法反演

Inversion on Slip Velocity of Main Faults in Weihe Basin by Particle Swarm Optimization Algorithm with GPS Data

摘要:

渭河盆地是我国典型的断陷盆地,是中国大陆地裂缝活动、地面沉降活动最剧烈的地区之一。本文利用2004-2007年间的GPS数据,采用粒子群算法与位错理论模型相结合,对渭河盆地主要断裂的三维滑动速率进行了反演计算分析。结果表明：（1）断裂活动性质与地质测量方法获得的结果基本一致：除韩城—华县断裂以张裂为主外,渭河盆地主要断裂均以正倾滑为主,并具有走滑特征,呈张裂的运动趋势;（2）从滑动速率来看,秦岭北侧大断裂速率最大,可达4.5mm/a。固关—宝鸡断裂活动最小,活动速率仅为1mm/a左右;（3）在趋势上与现有的地质资料基本一致,以EW向断裂活动最强,NE方向较强,而NW方向较弱,并且分布上呈现南强北弱的特征。

Abstract:

Weihe Basin is a typical fault basin,and is one of the strong underground fissures and ground subsidence regions in China.In this study,by using the particle swarm optimization algorithm combined with the dislocation model.The three dimension slip velocity of main faults are computed in Weihe Basin by using GPS data observed from 2004 to 2007.The results show that（1） characteristics of faults activity are consistent with geological results basically,except Hancheng-Huaxian opening fault,all other faults are normal dip faults;（2） the slip velocity of Qinling northern margin fault is the largest,about 4.5 mm/a,and that of Guguan-Baoji fault is the smallest,about 1 mm/a;（3） the activity of faults are strongest in EW direction,moderate in NE direction and weakest in NW direction.The characteristics of distribution is stronger in southern area and weak in northern area of the basin.