摘要
2023年2月6日土耳其东南部连续发生M_(w)7.8和M_(w)7.6大地震,强震动观测台网获取到了大量的强震动观测记录,利用两次地震的强震动记录,对比土耳其地区地震动预测方程,分析了地震动的衰减特征,探讨M_(w)7.8地震的震源破裂特征对近断层地震动空间分布、速度脉冲的产生及观测台站方位相关的地震动总残差的影响,采用随机有限断层三维地震动模拟方法给出了基于数值模拟记录的仪器地震烈度图,得到以下结论:(1)两次地震中地震动的震源效应明显强于土耳其地区浅地壳地震的平均震源效应,M_(w)7.8地震对中长周期地震动的震源效应比M_(w)7.6地震更强烈;(2)两次地震中远场地震动的非弹性衰减明显强于土耳其地区的平均水平;(3)M_(w)7.8地震中最强烈的地震动主要集中于卡赫拉曼马拉什—安塔基亚的狭长区域内,该区域观测记录普遍具有双向速度脉冲特征,地震动总残差与台站方位角有明显相关性,推断M_(w)7.8地震沿北东走向的东安纳托利亚断裂向北东向破裂传播,同时沿南南西走向的东安纳托利亚断裂的卡赫拉曼马拉什—安塔基亚段向南南西方向破裂传播;(4)模拟记录能大致反映近断层地震动强度及距离衰减特征,M_(w)7.8和M_(w)7.6地震中破裂面附近地震烈度分别达到Ⅸ和Ⅷ度,烈度分布主要受破裂断层和局部场地条件的影响.
Two great earthquakes with M_(w)7.8 and M_(w)7.6 successively hit southeast Turkey on 6 February 2023.The dense strong-motion observation networks captured large numbers of strong-motion recordings from both events.The recordings after manually processing were used to analyze the attenuation characteristics of ground motions by comparisons with the ground-motion prediction equations applicable for Turkey.We then investigated the spatial distribution of near-fault ground motions,the generation of pulse-like velocity waveforms,and the correlation between total residuals and station azimuths to provide some explanations on the source rupture characteristic of the M_(w)7.8 event.Finally,the stochastic finite-fault method was used to simulate the three-component ground motions for mapping the instrumental seismic intensity.The meaningful conclusions were drawn as following.(1)The source effects of both Turkey events on ground motions are significantly stronger than the mean effect for shallow crustal earthquakes over Turkey.The stronger source effects on ground motions at moderate-to-long periods are observed in M_(w)7.8 event than those in the M_(w)7.6 event.(2)Compared with the average level in Turkey,the far-field ground motions in both events showed the stronger anelastic attenuation.(3)The strongest ground motions in the M_(w)7.8 event are concentrated in a narrow region from Kahramanmaras in the north to Antakya in the south where most strong-motion recordings were characterized by the bilateral velocity pulse.The total residuals show a significant dependency on the station azimuth.Comprehensively considering these phenomena,we inferred that the M_(w)7.8 event ruptured to the northeast along the northeast-trending East Anatolia fault,meanwhile ruptured to the south-southwest along the south-southwest-trending Kahramanmaras-Antakya section of East Anatolia fault.(4)The simulated ground motions roughly describe the intensity of near-fault ground motions and the attenuation trend with distance.The instrumental seis
作者
王宏伟
强生银
温瑞智
任叶飞
WANG HongWei;QIANG ShengYin;WEN RuiZhi;REN YeFei(Key Laboratory of Earthquake Engineering and Engineering Vibration,Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,China;Key Laboratory of Earthquake Disaster Mitigation,Ministry of Emergency Management,Harbin 150080,China)
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2024年第8期2990-3003,共14页
Chinese Journal of Geophysics
基金
中国地震局工程力学研究所基本科研业务费专项(2020C05)
国家自然科学基金项目(U1901602)
黑龙江省自然科学基金项目(LH2020E021)资助。
关键词
土耳其大地震
强震动记录
衰减特征
震源破裂特征
地震动模拟
Great Turkey earthquakes
Strong-motion recordings
Attenuation characteristics
Source rupture characteristic
Ground-motion simulations
