关键词: 冷底辟, 热底辟, 地震信息, 构造与火山地震, 冷底辟破坏性地震

Abstract: Under the effect of external force,plastic layers in subsurface and deep crust would result in diapirism,and the resulting structure is called diapiric structure,which can be divided into two types according to their nature,one is cold diapir and other is hot diapir.Cold diapir is defined here as the structural style resulting from diapirism or upward movement of plastic material such as salt,gypsum and shale.Hot diapir is defined as the diapiric structural style resulting from magmatic intrusion or explosion.Both of them are characterized with chaotic internal reflection pattern and rapid termination of reflections relevant to surrounding rock in seismic section.Magmatic diapirism is commonly associated with high magnetic anomaly and high interval velocity.Some cold diapir is associated with low interval velocity,but the diapir resulting from gypsum is associated with high interval velocity.Hot diapir is undoubtedly linked to volcanic earthquake.Cold diapir can also result in disastrous earthquake which is commonly omitted by geologist.Such examples include:two earthquakes with M_S 7 1/4 and M_S 6 1/4 respectively taking place in Luntai(located in the front belt of South Tianshan Mts.between Koerle and Wushi)in 1949;the northeast Baicheng earthquake with M_S 7 1/4 in 1949;the south Baicheng earthquake with M_S 6 1/4 in 1947;and the Wushi earthquake with M_S 6.5 in 1969.The earthquakes mentioned above are obviously controlled by the large fault belt in the south of depression at the front of South Tianshan Mts.Among them,the Baicheng fault is a rootless one which is associated with Paleogene gypsum flow and upward movement.It is inferred that south Baicheng earthquake is related to the fault.Therefore,people working in seismogeology should pay more attention to the study of cold diapirism.

Key words: cold diapir, hot diaper, seismic information, tectonic and volcanic earthquake, disastrous earthquake resulting from cold diapirism