基于最大类间方差法的微动面波频散曲线自动提取及应用

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中图分类号：P631 文献标识码：A DOI：10.13810/j.cnki.issn.1000-7210.20250173

Abstract： Dispersion curve extraction is one of the key steps in microtremor investigation，and its accuracy directly affects the reliability of subsequent inversion results.Automatic picking of dispersion curves meets the requirements of large-scale data processing and therefore is of great significance for microtremor investigation. However，because microtremor is a passive-source signal， the energy in its dispersion spectrum is typically weak，which makes automatic picking challenging. To addressthis issue， this paper proposes an automatic extractionmethod for microtremor dispersion curve based on the maximum between-class variance method.The proposed approach first applies mean filtering to smooth the dispersion spectrum. Then，the dispersion curve region is determined from the smoothed dispersion spectrum through two successive applications ofthe maximum between-class variance method.Noise is further removed using a maximum connected-domain identification method.Finally，the algorithm automatically extracts the dispersion curve by selecting the energy peak velocities corresponding to all frequencies within the largest connected-domain. Thismethod effectively removes minor

energy interference in the dispersion spectrum and accurately locates and extracts the dispersion curve. Experiments on synthetic data show thatthe extracted dispersion curves are in good agreement with the theoretical dispersion curves，which demonstrates the accuracy ofthe algorithm.Experiments on real data，through 30 independent inversions and comparison with geological information，further verify thereliability of the method in practicalapplications.

Keywords： microtremor，surface wave，maximum between-class variance method，dispersion curve，automatic extraction

0 引言

微动是地球表面由自然或人文活动引起的微小震动，其信号蕴含丰富的面波信息，可用于反演地下横波速度结构，是一种绿色、经济的地下探测技术[1-5]。（剩余14308字）