The deepest lake in China, the Tianchi Lake of Changbai Mountain, is located in the southeast of Jilin Province. The water surface is 2150 meters above sea level, oval in shape, with an area of 9.82 square kilometers and a circumference of 13.1 kilometers. With an average water depth of 204 meters and a maximum depth of 373 meters, it is the deepest lake in China. The Tianchi Lake of Changbai Mountain is not an ordinary lake. It used to be a crater. Changbai Mountain erupted violently for many times in ancient times, forming a huge and deep crater. After the cessation of volcanism, atmospheric precipitation and groundwater gradually accumulated into a lake in the crater, creating the famous Tianchi Lake of Changbai Mountain.
Volcanic activity and volcanic dormancy can be divided into volcanic activity and volcanic death. Active volcanoes refer to volcanoes that are still active or periodically erupted. Etna volcano in Italy and Merapi volcano in Indonesia are all active volcanoes. An extinct volcano is a volcano that erupted in prehistoric times but has never been active in human history. In fact, the "death" of volcanoes is relative. Due to the continuous movement of the earth's crust and the repeated flow of underground magma, dead volcanoes may erupt again and become active volcanoes. Dormant volcanoes refer to volcanoes that have erupted in history but have been relatively static for a long time. Changbai Mountain is a dormant volcano. Its main activity occurred from 110 million to 30 million years ago. There were small-scale eruptions in the Ming and Qing Dynasties.
Changbaishan volcano is currently in dormancy. On the mountain with an altitude of more than 2000 meters, many hot springs continue to overflow from the ground. This shows that the underground is still pregnant with huge energy. According to modern earthquake observation, the crust of Changbai Mountain area is relatively stable, and there is no sign of eruption of Changbai Mountain volcano at present.