摘要
基于西昌流动台阵和安宁河断裂带附近固定台站2013—2019年记录的宽频带地震波形资料,利用波形互相关方法进行相似地震识别,同时对P,S震相到时进行校正。结合S−P相对到时差约束地震相对距离的方法,在安宁河断裂带及其周边地区识别得到10组重复地震。对研究区内近震事件和重复地震分别进行重定位,并根据重复地震发震时间间隔计算断裂带深部滑动速率。结果显示:汶川—茂县断裂带西南段滑动速率约为4.37—6.09 mm/a;安宁河断裂带北段滑动速率约为2.30 mm/a;木里地区滑动速率在2.03—8.46 mm/a之间。结合已有研究成果,推测汶川—茂县断裂西南段处于持续蠕滑状态,与孕震凹凸体附近的断层运动特征相符,暗示该区可能存在发生强震的风险;由重复地震和地震重定位结果推测安宁河断裂带具有北段蠕滑、南段闭锁的特征;木里地区浅部地震事件数量多于深部,且浅部滑动速率高于深部,符合水库诱发地震的特征。
Based on broadband seismic data recorded by the Xichang Array and permanent seismic stations near the Anninghe fault from 2013 to 2019,similar earthquake clusters were identified by means of waveform correlation and the correction of P-and S-wave arrival times.By constraining interevent distances based on the difference between S-and P-wave arrival times,10 groups of repeating earthquakes were identified in the Anninghe fault and its surrounding regions.Local events and repeating earthquakes in the studied area were relocated,and the recurrence interval of repeating earthquakes was used to estimate deep slip rates of the fault.It was found that slip rates in the southwestern section of the Wenchuan−Maoxian fault ranged from 4.37 to 6.09 mm/a.The slip rate in the northern segment of the Anninghe fault was 2.30 mm/a,and the slip rate in the Muli region ranged from 2.03 to 8.46 mm/a.It was thus inferred that the southwestern segment of the Wenchuan−Maoxian fault is continuously creep-ing,which is consistent with fault movements near seismogenic asperities.Therefore,a strong earthquake may occur in this area.Based on the identification of repeating earthquakes and earthquake relocation,it was concluded that the northern section of the Anninghe fault is cree-ping,while its southern section is locked.In the Muli region,shallow seismic events outnum-ber deep seismic events,and the shallow slip rate is higher than the deep slip rate,which is consis-tent with reservoir-induced seismicity.
作者
史克旭
周聪
张佩
张蒙
Shi Kexu;Zhou Cong;Zhang Pei;Zhang Meng(Second Monitoring and Application Center,China Earthquake Administration,Xi’an 710054,China)
出处
《地震学报》
CSCD
北大核心
2023年第4期658-670,共13页
Acta Seismologica Sinica
基金
陕西省自然科学基础研究计划项目(2022JQ-256)
国家自然科学基金青年基金(41904063)
国家重点研发计划项目(2018YFC1503400)
中国地震局第二监测中心科学技术基金(KJ20200103)共同资助.
