基于背景噪声成像的沂沭断裂带及邻区波速变化

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中图分类号：P631.4 文献标志码：A

Abstract： The Yishu fault zone is located in the middle section of the Tanlu fault zone，consisting of multiple nearly north-northeast trending faults. Significant variations in crustal structure are present on both sides of the fault zone. The seismic velocity and velocity variations are important parameters for understanding the deep structural characteristics of the earth and the potential damage of the medium. Based on the continuous seismic waveforms from permanent stations in the Yishu fault zone and surrounding regions from January 20ll to December 20l4，we perform ambient noise tomography to monitor the phase velocity variations of Rayleigh wave. The results show that the velocity variations correlate well with the small earthquake activities. The earthquakes （ ∇⋅M>2 ）are mainly concentrated near the velocity reduction and velocity transition zones.The velocity variations near the Yishu fault zone are not significant，indicating that the fault activity is relatively weak recently. The velocity variations in the Jiaobei uplift are notable between 2Ol3 and 2014，which is related to surface deformation.It is speculated that the compression effect of regional stress is the main factor for the velocity increase in the Jiaobei uplift.

Key words： Yishu fault zone； ambient noise tomography； velocity variation； small earthquakeactivity

0 引言

地震波速测量是监测地壳介质变化的重要技术，在探究地球内部构造与动力学方面有着十分重要的作用[1-2]。（剩余17736字）