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

Abstract: 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 comparing 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.

Key words: damping least-squares method, joint inversion, Changbaishan-Tianchi volcano, magma activity characteristic