关键词: 天池火山, 水准测量, GPS, 地壳变形

Abstract: In order to monitor the activity of Tianchi Volcano in the Changbai Mountains,a comprehensive geodetic monitoring network consisting of precise leveling and GPS stations,has been established since 2000.In this paper,we first introduce the installation of the geodetic network and then discuss the deformation results around the volcanic area. The results show that from 2002 to 2005,obvious ground deformation occurred in the Tianchi volcano area in the Changbai Mountains.In the vertical direction,the cumulative elevation difference of leveling line reached 6.8cm in the 3 years,and the nearer to the crater,the greater the deformation was.In the horizontal direction,centered on the crater,the observation stations showed a radial displacement in general,with the maximum up to 38cm.Significant expansion occurred in the mountains,and the maximum surface expansion was up to 6?10^-6/a.After 2006,these changes resumed to normal gradually.In the meantime,the Tianchi volcanic area of Changbai Mountains saw frequent volcanic seismicity,and other monitoring data also showed abnormal changes synchronously. The paper analyzes and discusses the possible reasons for these changes,and concludes that these changes may be the result of the latest magmatic activity of Tianchi volcano.

Key words: Tianchi volcano, precise leveling, GPS, crust deformation