Mogi模型在长白山天池火山区的应用  

APPLICATION OF MOGI MODEL AT CHANGBAISHAN TIANCHI VOLCANO

作　　者：胡亚轩[1] 王庆良[1] 崔笃信[1] 王文萍[1] 李克[2] 陈红卫[1] 

机构地区：[1]中国地震局第二监测中心,西安710054 [2]吉林省地震局,长春130022

出　　处：《地震地质》2007年第1期144-151,共8页Seismology and Geology

基　　金：国家自然科学基金(40574041);地震科学联合基金(605004)共同资助

摘　　要：文中首先介绍了Mogi模型的阻尼最小二乘反演,得出应用形变资料联合反演压力源参数的公式,再指出用等效源半径反演时不同初始值对反演结果的影响,说明选择合适的初始值可以方便地得到可靠的反演结果。然后用此方法反演长白山天池火山区压力源的大小和位置参数。采用垂直和水平位移的联合反演,数据为2002—2005年共4期的水准和GPS观测资料,最后结合其它观测资料,分析近年来岩浆可能的活动特征。结果显示岩浆的位置在发生变化,体积增量逐年减小,表明火山岩浆在2002—2005年的活动逐年减弱。Classical least-squares methods have been used widely. For Mogi model, the product about the partial derivative matrix A is singular when the changing size is small, so damping least-squares method is chosen. The method is introduced at first in the paper. In order to conquer the limitation to vertical deformation, the inversion formula of Mogi model with vertical and horizontal rates is gotten. Before the inversion is run, the initial data of different parameters are given based on other researches. From the scale relation between rates and R, the different initial R can be obtained. Through compa- ring the inversion results using those different initial R, the proper initial data assumption is chosen. At last, with proper damping least-squares method, the magma source position and changing size are inversed in Changbaishan-Tianchi volcano using four periods of leveling measurements and GPS data during 2002--2005. Here, the regional rates can show the volcano activity well, so the GPS velocity during different periods is calculated based on mean reference （the velocities related to mean site rates）. The source parameters are inversed jointly with vertical and horizontal data. The position near to the source is inversed by earthquake data. Considering other analyses at the same time, the following results are gotten： the magma positions change with time, its volume increment becomes smaller after 2003 and the magma activity becomes weaker.

关 键 词：阻尼最小二乘法 联合反演 长白山天池火山 岩浆活动特征 

分 类 号：P317[天文地球—固体地球物理学]