地震-电成像联合探测试验——以淄博市活断层探测为例
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摘要
在城市浅部活断层探测中,地震和电成像是2种主要的地球物理勘探手段。它们既可独立开展工作,也可在地质构造复杂地段进行联合探测,以更合理地解释探测区域的地质构造。文中利用电阻率和地震纵波速度之间的简单关系,进行了地震-电成像联合反演的初步探索。结果表明,通过参考电成像图像的电阻率分布,可获得合理的准二维地震波叠加速度模型,最终获得探测区域合理的地震时/深剖面,深化对地质构造的认识和提供合理的解释。
In exploration of a shallow active fault in urban area,seismic reflection survey and electrical imaging are the two main geophysical tools.Both of them can be implemented independently.However,the complexity of subsurface geologic tectonics,especially the lateral irregularities close to fault and geologic tectonic zones could result in great deviation from the detected results.In the meantime,the geophysical inversion has not only one result.These would lead to a large difference of stacked velocity model established only by its own information from real one in seismic data processing.In consequence,the geologic interpretation would be harmed.On the other hand,electrical imaging is very sensitive to the lateral irregularities of rock properties but has weak resolution in depth.Therefore,the two techniques can just compensate each other and a joint detection can be carried out to interpret a complex geologic tectonics more reasonably.In this paper,experiment on the joint detection using seismic reflection survey and electrical imaging is made basing on the simple relationship between resistivity and seismic P-wave velocity:ρa∝|Z|2∝V2p.It is shown that a reasonable quasi 2-D seismic stacked velocity model can be obtained referring to the resistivity image from electrical imaging.In the end,the reasonable seismic reflection and time-depth conversion profiles are gotten,which is helpful for further understanding and more reasonably interpreting the geological structures.
In exploration of a shallow active fault in urban area,seismic reflection survey and electrical imaging are the two main geophysical tools.Both of them can be implemented independently.However,the complexity of subsurface geologic tectonics,especially the lateral irregularities close to fault and geologic tectonic zones could result in great deviation from the detected results.In the meantime,the geophysical inversion has not only one result.These would lead to a large difference of stacked velocity model established only by its own information from real one in seismic data processing.In consequence,the geologic interpretation would be harmed.On the other hand,electrical imaging is very sensitive to the lateral irregularities of rock properties but has weak resolution in depth.Therefore,the two techniques can just compensate each other and a joint detection can be carried out to interpret a complex geologic tectonics more reasonably.In this paper,experiment on the joint detection using seismic reflection survey and electrical imaging is made basing on the simple relationship between resistivity and seismic P-wave velocity:ρa∝|Z|2∝V2p.It is shown that a reasonable quasi 2-D seismic stacked velocity model can be obtained referring to the resistivity image from electrical imaging.In the end,the reasonable seismic reflection and time-depth conversion profiles are gotten,which is helpful for further understanding and more reasonably interpreting the geological structures.
引文
[1]Tseng Het al.,2001,Joint inversion for mapping subsurface hydrological parameters,http://repositories.cdlib.org/lbnl/LBNL-47607。
[1]山东省工程研究院,2006,淄博市活断层探测与地震危险性评价技术报告。
邓起东,徐锡伟,张先康,等.2003.城市活动断裂探测的方法和技术[J].地学前缘,10(1):93—104.DENG Qi-dong,XUXi-wei,ZHANG Xian-kang,et al.2003.Methods and techniques for prospecting active faults inurban areas[J].Earth Science Frontier,10(1):93—104(in Chinese).
王兴泰,李晓芹.1995.电阻率图像重建的佐迪(Zohdy)反演及其应用效果[J].物探与化探,20(3):228—233.WANG Xing-tai,LI Xiao-qin.1995.The image reconstruction of electric resistivity by Zohdy inversion and its applica-tion effects[J].Geophysical&Geochemical Exploration,20(3):228—233(in Chinese).
Cardarelli E,Marrone C,Orlando L.2003.Evaluation of tunnel stability using integrated geophysical methods[J].JAppl Geophys,52:93—102.
Feng R,He Z Q,Wu Q J,et al.1998.Joint imaging fractures from resistivity and seismic surveys[J].Proceedingsof the3rdInternational Symposium on Recent Advances in Exploration Geophysics in Kyoto.86—90.
Gallardo L A,Meju M A.2003.Characterization of heterogeneous near-surface materials by joint2D inversion of DCresistivity and seismic data[J].Geophysical Research Letters,30(13):1658—1661.
Greer A A.1999.Use of effective medium techniques to integrate seismic and controlled source electromagnetic data[J].Lithos Science Report,1:111—114.
Hering A R,Misiek A,Gyulai M,et al.1995.A joint inversion algorithm to process geoelectric and surface waveseismic data.Part I:basic ideas[J].Geophys Prosp,43:135—156.
Leucci G,De Giorgi L.2005.Integrated geophysical surveys to assess the structural conditions of a karstic cave of ar-chaeological importance[J].Natural Hazards and Earth System Sciences,5:17—22.
Manglik A,Verma K.1998.Delineation of sediments belowflood basalt by joint inversion of seismic and magnetotellu-ric data[J].Geophysical Research Letters,25:4015—4018.
Meju MA,Gallardo LA,Mohamed AK.2003.Evidence for correlation of electrical resistivity and seismic velocity inheterogeneous near-surface materials[J].Geophys Res Lett,30(7):26,10.1029/2002GL016048.
Pandey D.2000.Joint inversion of seismic and EMdata for sub-basalt imaging from central western part of India[J].Lithos Science Report,2,133—136.
Warren R K.1996.A fewcase histories of subsurface imaging with EMAP as an aid to seismic prospecting and inter-pretation[J].Geophysical Prospecting,44:923—934.
Zhang J,Morgan F D.1996.Joint seismic and electrical tomography[A].In:Proc EEGS Symposium on Applica-tions of Geophysics to Engineering and Environmental Problems,Keystone,Colorado.391—396.
[1]山东省工程研究院,2006,淄博市活断层探测与地震危险性评价技术报告。
邓起东,徐锡伟,张先康,等.2003.城市活动断裂探测的方法和技术[J].地学前缘,10(1):93—104.DENG Qi-dong,XUXi-wei,ZHANG Xian-kang,et al.2003.Methods and techniques for prospecting active faults inurban areas[J].Earth Science Frontier,10(1):93—104(in Chinese).
王兴泰,李晓芹.1995.电阻率图像重建的佐迪(Zohdy)反演及其应用效果[J].物探与化探,20(3):228—233.WANG Xing-tai,LI Xiao-qin.1995.The image reconstruction of electric resistivity by Zohdy inversion and its applica-tion effects[J].Geophysical&Geochemical Exploration,20(3):228—233(in Chinese).
Cardarelli E,Marrone C,Orlando L.2003.Evaluation of tunnel stability using integrated geophysical methods[J].JAppl Geophys,52:93—102.
Feng R,He Z Q,Wu Q J,et al.1998.Joint imaging fractures from resistivity and seismic surveys[J].Proceedingsof the3rdInternational Symposium on Recent Advances in Exploration Geophysics in Kyoto.86—90.
Gallardo L A,Meju M A.2003.Characterization of heterogeneous near-surface materials by joint2D inversion of DCresistivity and seismic data[J].Geophysical Research Letters,30(13):1658—1661.
Greer A A.1999.Use of effective medium techniques to integrate seismic and controlled source electromagnetic data[J].Lithos Science Report,1:111—114.
Hering A R,Misiek A,Gyulai M,et al.1995.A joint inversion algorithm to process geoelectric and surface waveseismic data.Part I:basic ideas[J].Geophys Prosp,43:135—156.
Leucci G,De Giorgi L.2005.Integrated geophysical surveys to assess the structural conditions of a karstic cave of ar-chaeological importance[J].Natural Hazards and Earth System Sciences,5:17—22.
Manglik A,Verma K.1998.Delineation of sediments belowflood basalt by joint inversion of seismic and magnetotellu-ric data[J].Geophysical Research Letters,25:4015—4018.
Meju MA,Gallardo LA,Mohamed AK.2003.Evidence for correlation of electrical resistivity and seismic velocity inheterogeneous near-surface materials[J].Geophys Res Lett,30(7):26,10.1029/2002GL016048.
Pandey D.2000.Joint inversion of seismic and EMdata for sub-basalt imaging from central western part of India[J].Lithos Science Report,2,133—136.
Warren R K.1996.A fewcase histories of subsurface imaging with EMAP as an aid to seismic prospecting and inter-pretation[J].Geophysical Prospecting,44:923—934.
Zhang J,Morgan F D.1996.Joint seismic and electrical tomography[A].In:Proc EEGS Symposium on Applica-tions of Geophysics to Engineering and Environmental Problems,Keystone,Colorado.391—396.
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