西秦岭北缘断裂带土壤气定点监测与初步结果分析

根据前人对西秦岭北缘断裂带上历史地震及古地震复发周期和离逝时间等的综合研究,得出该断裂存在发生强震的较大潜在风险,因此加强对该断裂现今构造活动的定点监测和地震预测预报具有重要现实意义.据此,根据断裂逸出气体测项剖面浓度分布(变化)特征,在西秦岭北缘断裂带(天水段)上新建3个断层土壤气连续观测站,开展断层气(H2、CO2...

Preliminary analysis results of fixed-point monitoring on soilgas along the northern margin fault of West Qinling

According to the previous study on the historical earthquakes and the recurrence cycle and elapsed time of paleoearthquakes along the northern margin fault zone of West Qinling, a great potential risk of strong earthquakes exists in the fault. Therefore, it is of great practical significance to strengthen the fixed-point monitoring and earthquake prediction of current tectonic activity of the fault. In this paper, according to the profile concentration distribution (variation) characteristics of gas escaping from the fault, three stations for continuous observation on fault soil gas were newly built in the Tianshui section. Then the concentration observation of fault gas (H₂, CO₂, Rn, CH₄) was carried out to analyze the spatial difference of deep gas characteristics in different sections of the fault zone and their variation characteristics with time. In this way, the stress adjustment and seismicity in southeast Gansu were monitored. The analysis of preliminary observation data showed that the background value is relatively stable under normal conditions, and the change patterns of the same measurement item at different measurement points are similar and synchronous, indicating that the observation data are true, reliable and comparable. The synchronous abnormal change of measured item at different measuring point may reflect the regional stress adjustment and change, thus providing a reference criterion for earthquake tracking and prediction.