长白山天池火山近期形变场演化过程分析

对长白山天池火山区2002～2005年的4期水准测量数据、2000～2005年6期GPS测量数据以及1999年以来的定点地倾斜观测数据进行了系统处理分析，结果表明：（1）2000年9月～2002年6月期间，长白山天池火山地表变形很小，基本上处于较为稳定的状态. 1993～1998年的InSAR观测资料也未发现明显的地表变形；（2）2002～2003年，长白山天池火山出现了明显的地表形变异常变化，其水平形变表现为以天池火山口为中心的放射状膨胀运动，垂直形变则表现为近火山口的快速隆起，显示天池火山下部可能有岩浆压力增大变化；（3）长白山天池火山2003年以来的形变速率有逐年迅速衰减的变化特征，其最大水平运动速率已由2002～2003年期间的38.3mm/a衰减到2004～2005年的15.8mm/a，最大垂直形变速率则由2002～2003年的46.0mm/a 衰减到2004～2005年的5.0mm/a.

Analysis of recent deformation of Changbaishan Tianchi volcano

The observation data of four leveling measurement campaigns between 2002 and 2005,six GPS surveys between 2000 and 2005 as well as the continuous tilt observation from 1999 to 2004 are systematically processed in this paper.The results demonstrate that:(1) From September 2000 to June 2002,the Tianchi volcano is basically in the quiescence status with no obvious deformation detected by GPS and InSAR observations;(2) In 2002 and 2003 there is abnormal surface deformation in the Tianchi volcano.The horizontal deformations derived from GPS observations display a typical radiation movement pattern with center at the crater lake,and leveling measurements also reveal rapid uplift around the lake;(3) The unrest process seems to have decayed rapidly year by year,for example,the maximum horizontal radiation movement of the GPS sites has decreased from a rate of 38.3mm/a between September 2002 and September 2003 to 15.8mm/a between September 2004 and September 2005,the maximum uplift rate of the leveling points also has decreased from 46.0mm/a between June 2002 and September 2003 to 5.0mm/a between September 2004 and September 2005.