摘要
作者在研究了滇西地区碳酸泉的分布及其同位素组成特征后提出,该区存在五种不同成因机制的CO_2释放.其中,深源CO_2混合成因和热动力变质成因CO_2的释放与地壳深部应力状态的变化关系密切,因而具有较好的映震效能.对下关、江干等典型泉点的CO_2释放的连续观测表明,在该区发生五级左右地震前,地热流体的溶解CO_2总量有明显的异常变化,其中短临前兆变化十分引人注目.因此,监测这类碳酸泉的CO_2释放有可能是一种有效的地震前兆观测方法.
The authors have studied the distribution of CO2 springs in western Yunnan and their isotopic composition,and suggested that there are five different sources of CO2 discharges inthat area. They are: (1) areal metamorphic origin----the Daxing CO2 spring in YunxianCounty; (2) aureloe metamorphic origin----the hot CO2 springs in the Tengchong geothermalarea; (3) remanent volcanic origin----the cold CO2 springs in the Tengchong area; (4) thermaldynamometamorphic origin----the CO2 springs in Eryuan County; (5) the mixed origin ofmetamorphic and mantle COa----other CO2 springs distributed along the deep-great faults.Among them the mixed origin and the thermal dynamometamorphic origin CO2 discharges are related intimately to the tectonic stress change in the deep crust,therefore the capability of reflecting earthquake activity is better. We have selected the typical springs at Xiaguan and Jianggan to monitor continually the possible relations between the CO2 discharges and seismic activities. The monitoring results indicated chat,the total dissolved CO2 content in the thermal fluid showed distinctly anomalous changes before earthquakes of magnitude about 5.0 in that area,and the imminent precursor was very noticeable; and therefore monitoring the total dissolved CO2 content of the CO2 springs could be a useful method for earthquake prediction.
出处
《地震学报》
CSCD
北大核心
1990年第2期186-193,225,共8页
Acta Seismologica Sinica
