马头营干热岩开采试验场地人工注水诱发地震探讨OA北大核心CSTPCD

Based on the seismic observation data of 7 temporary seismic stations in the hot dry rock area of Matouying and the pressurized water injection data of M1 well from 2022-06 to 09,we study the relationship between seismic activity,water injection pressure and water flow;we further study the focal mechanism of in-duced earthquakes and analyze their influence on the surrounding stress field.The results show that 201 earthquakes may be induced by water injection operation,and the focal depth is mainly concentrated in 0-4 km.This area is also a safe area with small ground confining pressure,and the probability of moderate and strong earthquakes is small.The changes of water flow and water pressure not only affect the temporal and spatial distribution characteristics of induced earthquakes,but also affect the frequency of seismic activity.When the stress accumulates to a certain level to induce earthquakes,the water flow,water pressure and earthquake frequency show a positive correlation.The relationship between the amount of water injected and the earthquake magnitude is not obvious,and the pressure is linearly correlated with the induced earthquake magnitude.When the continuous water injection volume reaches 11 821 m3 and the pressure reaches 23.46 MPa,the fault instability may induce earthquake.The focal mechanism of the maximum induced earthquake is strike-slip type,and the principal compressive stress is NNW,which has a certain deviation from the stress distribution in North China.It can be seen that the mining of M1 well has an effect on the local stress distri-bution.According to the migration rule of earthquake epicenter,there are new ground cracks.