CAJ | 학술논문

基于 Coulomb3．3软件，通过研究地震累加与单震的库仑应力变化对后续地震的触发关系，对北祁连山东段及邻区自1561年以来的9次强震静态库仑应力变化进行了研究。结果表明：对于叠加现象来说，后一地震事件除了门源地震落在应力影区外，先前地震活动对后续地震都产生了明显的触发作用，库仑应力变化在0．1～4．066 bar 之间；而对于单独事件的应力变化，断层距较小的地震之间相互触发的影响较大。根据库仑应力变化和年应力累积量的比值，得出地震在没有先前地震作用下还需要的应力累积时间。最后根据大震后区域断裂库伦应力变化及断裂强震活动历史等特征，对本区未来强震地震危险性进行分析，得出本区未来地震危险区位于云雾山断裂以及天祝-景泰-古浪一带的金强河断裂上。
기우 Coulomb3．3연건，통과연구지진루가여단진적고륜응력변화대후속지진적촉발관계，대북기련산동단급린구자1561년이래적9차강진정태고륜응력변화진행료연구。결과표명：대우첩가현상래설，후일지진사건제료문원지진락재응력영구외，선전지진활동대후속지진도산생료명현적촉발작용，고륜응력변화재0．1～4．066 bar 지간；이대우단독사건적응력변화，단층거교소적지진지간상호촉발적영향교대。근거고륜응력변화화년응력루적량적비치，득출지진재몰유선전지진작용하환수요적응력루적시간。최후근거대진후구역단렬고륜응력변화급단렬강진활동역사등특정，대본구미래강진지진위험성진행분석，득출본구미래지진위험구위우운무산단렬이급천축-경태-고랑일대적금강하단렬상。
Earthquakes are a natural phenomenon caused by sudden rupture and slippage of crustal rocks after stress reaches the point of rock failure.The coseismic dislocations of a major earth-quake not only cause the stress state changes in adjacent areas,but also change the Coulomb stress.Research shows that a very small static Coulomb stress changes can trigger seismic activity (i.e.,earthquakes).Therefore,it is important to explore the relationship between Coulomb stress changes and earthquake triggering.First of all,we conducted primary research for strong earth-quakes by Coulomb 3.3 on the static Coulomb stress changes with the primary study region being the eastern margin of north Qilian Mountain and adjacent area from 1561 to present.Meanwhile, we used cumulative and individual methods to calculate the Coulomb stress changes between fore-shocks and aftershocks.Our results show that the next events,except Menyuan earthquake in 1986,would occur in the stress triggering area.The value of changes is between 0.1 bar and 4.066 bar,and trigger rate reached a high of 87.5%.In other instances,when the source fault is closed to receive fault,the former event can trigger the next.Secondly,according to the relationship be-tween Coulomb stress changes and stress accumulation rate,we calculated the stress accumulated before the next event,not considering foreshocks.Finally,we assessed the future strong seismic hazard for this area according to earthquake migration and stress triggering.We used Okada’s method to calculate the change of static Coulomb failure stress among faults for the study area.In 1920 and 1927,two magnitude 8 earthquakes occurred,prior to the earthquakes the Coulomb stress significantly increased in the eastern side of Yunwu Mountain and western part of Jingtai-Tianzhu- Gulang.This suggests that an increase of Coulomb stress may forecast a triggered earthquake.It is noteworthy that the Tianzhu 6.2 earthquake occurred in the western part of the danger zone after two prior earthquakes.Considering the Coulomb stress triggering and the histo-ry of seismic activity,future earthquake risk should be strong in this area as well as the eastern side of Yunwu Mountain and Jinqianghe fault zone in the western part of Jingtai-Tianzhu-Gulang. This paper attempts to combine Coulomb stress adjustment and fracture characteristics with seis-mic activity.Results are consistent with other approaches in the Northeastern Qilian area,indica-ting that Coulomb stress changes can be used as an indicator of oncoming seismic activity.Appli-cation of this method will require further improvement to assess future seismic risk.