地震学报
地震學報
지진학보
ACTA SEISMOLOGICA SINICA
2015年
2期
323-334
,共12页
李娜%何正勤%叶太兰%房慎冲
李娜%何正勤%葉太蘭%房慎遲
리나%하정근%협태란%방신충
天然源面波勘探%台阵布局%人工源面波勘探
天然源麵波勘探%檯陣佈跼%人工源麵波勘探
천연원면파감탐%태진포국%인공원면파감탐
natural source surface wave exploration%array layout%artificial source surface wave exploration
为了对比天然源面波勘探不同台阵布局的探测效果，筛选出探测成果可靠、效率高和便于野外施工的天然源面波勘探台阵阵形，在天水市黄土覆盖区的同一场地分别用4种常见的阵形进行数据采集试验，并对各种阵形数据使用空间自相关法或扩展空间自相关法提取相应的频散曲线，通过反演得到了试验点地下的浅层速度结构模型。分析对比试验结果表明：4种台阵提取的频散曲线数值很相近；频散谱能量集中度较高的是嵌套式等边三角形和圆形台阵，L 形和直线形台阵相对分散；L 形台阵低频段（4—8 Hz）比直线形台阵差，其高频段（8—40 Hz）比直线形台阵好。针对直线形台阵在高频段信噪比较低的情况，在确保探测成果可靠性的前提下，为了提高探测效率，提出了在同一直线形台阵开展天然源与人工源面波联合勘探的数据采集方法。实验结果证实，这种联合勘探方法不仅可弥补直线形台阵高频段的不足，确保探测精度和结果的可靠性，而且还能实现“高低”频兼顾，即“深浅”兼顾。
為瞭對比天然源麵波勘探不同檯陣佈跼的探測效果，篩選齣探測成果可靠、效率高和便于野外施工的天然源麵波勘探檯陣陣形，在天水市黃土覆蓋區的同一場地分彆用4種常見的陣形進行數據採集試驗，併對各種陣形數據使用空間自相關法或擴展空間自相關法提取相應的頻散麯線，通過反縯得到瞭試驗點地下的淺層速度結構模型。分析對比試驗結果錶明：4種檯陣提取的頻散麯線數值很相近；頻散譜能量集中度較高的是嵌套式等邊三角形和圓形檯陣，L 形和直線形檯陣相對分散；L 形檯陣低頻段（4—8 Hz）比直線形檯陣差，其高頻段（8—40 Hz）比直線形檯陣好。針對直線形檯陣在高頻段信譟比較低的情況，在確保探測成果可靠性的前提下，為瞭提高探測效率，提齣瞭在同一直線形檯陣開展天然源與人工源麵波聯閤勘探的數據採集方法。實驗結果證實，這種聯閤勘探方法不僅可瀰補直線形檯陣高頻段的不足，確保探測精度和結果的可靠性，而且還能實現“高低”頻兼顧，即“深淺”兼顧。
위료대비천연원면파감탐불동태진포국적탐측효과，사선출탐측성과가고、효솔고화편우야외시공적천연원면파감탐태진진형，재천수시황토복개구적동일장지분별용4충상견적진형진행수거채집시험，병대각충진형수거사용공간자상관법혹확전공간자상관법제취상응적빈산곡선，통과반연득도료시험점지하적천층속도결구모형。분석대비시험결과표명：4충태진제취적빈산곡선수치흔상근；빈산보능량집중도교고적시감투식등변삼각형화원형태진，L 형화직선형태진상대분산；L 형태진저빈단（4—8 Hz）비직선형태진차，기고빈단（8—40 Hz）비직선형태진호。침대직선형태진재고빈단신조비교저적정황，재학보탐측성과가고성적전제하，위료제고탐측효솔，제출료재동일직선형태진개전천연원여인공원면파연합감탐적수거채집방법。실험결과증실，저충연합감탐방법불부가미보직선형태진고빈단적불족，학보탐측정도화결과적가고성，이차환능실현“고저”빈겸고，즉“심천”겸고。
In order to select the array layout with high efficiency and convenience for surface wave exploration using natural sources,four tests for data acquisi-tion with different layout are carried out in the same field.Then we perform comparative analysis of the dispersion curves extracted by using SPAC and ESPAC for different array layout.And then the velocity structure of the shal-low layer is obtained by inversion.Test results show that the dispersion curves extracted from the four arrays are very similar,and spectrum energy in the fre-quency domain is more concentrated for the nested equilateral triangle and circu-lar arrays than that for the linear and L-shape arrays.The dispersion curve ex-tracted from the L-shape array is better than the linear array in the high fre-quency band (8—40 Hz),while worse in the low frequency band (4—8 Hz). Since worse dispersion appears at high frequencies for the linear array,a joint exploration with both artificial and natural sources is proposed.The test result proves that the joint method can not only improve the quality of dispersion curve in the high frequency band to ensure the reliability of the detection precision, but also achieve dispersion data in a much broader frequency range.Conse-quently both shallow and deeper structure can be obtained in the inversion.
