腾冲火山区地震的震源参数  

Focal Parameters of Earthquakes in Tengchong Volcanic Area

作　　者：刘学军[1] 叶建庆[1] 蔡绍平[1] 蔡明军[1] 

机构地区：[1]云南省地震局,云南昆明650041

出　　处：《防灾减灾工程学报》2004年第1期22-27,共6页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家科技部社会公益项目资助课题(2001DIA10003)

摘　　要：火山区地震与非火山区或者说一般构造区地震的震源参数有何差异?本文使用2002-06-13～09-13腾冲火山区流动数字地震观测台网记录到的火山区地震资料,用波谱分析方法测算腾冲火山区地震的震源力学参数。对其中33个地震分析得出:腾冲火山区的地震震源浅,震级偏小;地震矩M0在8.32×1010～8.96×1012N·m之间;震级与地震矩之间的关系式为logM0=0.98ML+10.48,与姚安构造区得出的结果基本一致;震源位错半径在0.124～0.418km;地震应力降在(0.005～0.277)×105Pa,仅为姚安构造区地震应力降的1/5。这些结果表明腾冲火山区存在浅的岩浆体活动,在该区无大的应力积累。What are the differences of focal parameters between earthquakes in volcanic region and other region? A network with 15 sets of EADS-3M mobile digital seismic recorders were set up in Tengchong volcanic region from 2002-06-13 to 2002-09-13. More than 400 earthquakes in this region and adjacent areas were recorded. 33 records were selected to calculate focal dynamic parameters in Tengchong volcanic region by spectrum analysis method. Result calculated from S-wave is used to discuss varied time-spatial-intensity parameters. The earthquake in Tengchong is shallow earthquake with smaller magnitude. Scalar seismic moment in Tengchong is varied between 8.32E10 and 8.96E12 N·m. The relation between scalar seismic moment and local magnitude in Tengchong is logM_0=0.98M_L+1048 which is esentially identical to logM_0=0.99M_L+1043 in adjoined Yao'an tectonic area. Focal dislocation is in the range of 0.124 km to 0.418 km in Tengchong region. The stress drop is in the range of 0.005 MPa to 0.277 MPa. The value at most is only one-fifth of 0.021 MPa^19.4 MPa in Yao'an tectonic area. This might be the answer to the above question. The results also show the magma activity and derivational earthquake in shallow crust in Tengchong volcanic region. Lower crust stress here show lower stress accumulation.

关 键 词：腾冲火山区 火山地震 震源参数 波谱分析 力学 

分 类 号：P315.33[天文地球—地震学]