关键词: 长白山天池, 火山地震, 气体地球化学

Abstract: The recent fluid monitoring shows that mantle-derived CO₂,He and CH₄ content increased anomalously in 2002 and 2003. The ³He/⁴He ratio of deep-fault-type Jinjiang hot springs increased highly anomalously in 2003, and than decreased in 2004. That ratio from thermal-reservoir-type Changbaijulong hot springs increased slowly in 2003, and also increased continuously in 2004. Mantle-derived He content of releasing He from Changbaijulong springs increased obviously in 2004. The changes of releasing gases and He isotope corresponded to the trend of seismic activities in Tianchi volcanic area to a certain extent between 2002 and 2003. The abnormal release of Jinjiang decreased apparently after the seismic activities decreased in next half year of 2004, but the abnormal release from Changbaijulong increased highly after these seismic activities. It shows that the abnormal release of magmas-derived gases from thermal-reservoir-type springs lags behind that of the deep-fault-type springs. These characteristics are of great significance for identifying deep magmatic activity and predicting volcanic earthquake in the future.

Key words: Changbaishan Tianchi, volcanic earthquake, gas geochemistry