Imaging complex structure in shallow seismic-reflection data using prestack depth migration

Prestack depth migration PSDM analysis has the potential to significantly improve the accuracy of both shallow seismicreflectionimagesandthemeasuredvelocitydistributions.InastudydesignedtoimagefaultsintheAlvordBasin, Oregon, at depths from 25‐1000 m, PSDM produced a detailed reflection image over the full target depth range. In contrast, poststack time migration produced significant migration artifacts in the upper 100 m that obscured reflection events and limited the structural interpretation in the shallow section. Additionally, an abrupt increase from 2500 to 3000 m/s in the PSDM velocity model constrained the interpretation of the transition from sedimentary basin fill to basementvolcanicrocks.PSDManalysisrevealedacomplex extensional history with at least two distinct phases of basin growthandamidbasinbasementhighthatformsthedivision betweentwomajorbasincompartments.

[1]  Lee M. Liberty.  Seismic Reflection Imaging of a Geothermal Aquifer in an Urban Setting , 1998 .

[2]  Alan R. Levander,et al.  Migration moveout analysis and depth focusing , 1993 .

[3]  Glacial structures in northern Germany revealed by a high-resolution reflection seismic survey , 1998 .

[4]  Kamal M. Al-Yahya,et al.  Velocity analysis by iterative profile migration , 1987 .

[5]  J. Evans,et al.  Geologic field-trip guide to Steens Mountain Loop Road, Harney County, Oregon , 2001 .

[6]  S. Mahan,et al.  Unusually Low Rates of Slip on the Santa Rosa Range Fault Zone, Northern Nevada , 2005 .

[7]  R. F. King,et al.  The essentials of shallow reflection data processing , 1992, Quarterly Journal of Engineering Geology.

[8]  R. R. Compton,et al.  Quicksilver deposits of Steens Mountain and Pueblo Mountains, southeast Oregon , 1953 .

[9]  R. E. Wallace.  Patterns and timing of Late Quaternary faulting in the Great Basin Province and relation to some regional tectonic features , 1984 .

[10]  I. Effimoff,et al.  Tertiary structural development of selected valleys based on seismic data: Basin and Range province, northeastern Nevada , 1981, Philosophical transactions of the Royal Society of London. Series A: Mathematical and physical sciences.

[11]  A. Levander,et al.  Depth image focusing in traveltime map‐based wide‐angle migration , 2002 .

[12]  Prestack Kirchhoff depth migration of shallow seismic data , 1998 .

[13]  Jerry P. Fairley,et al.  Geostatistical evaluation of permeability in an active fault zone , 2003 .

[14]  S. Deregowski,et al.  What is DMO , 1986 .

[15]  Ning Guo,et al.  Becoming effective velocity-model builders and depth imagers, Part 2—The basics of velocity-model building, examples and discussions , 2002 .

[16]  Ray J. Weldon,et al.  Tectonic role of active faulting in central Oregon , 1993 .

[17]  James L. Davis,et al.  Targeting of Potential Geothermal Resources in the Great Basin from Regional Relationships Between Geodetic Strain and Geological Structures , 2002 .

[18]  J. Bradford.  Applying Reflection Tomography in the Postmigration Domain to Multifold Ground-Penetrating Radar Data , 2006 .

[19]  Christof Stork,et al.  REFLECTION TOMOGRAPHY IN THE POSTMIGRATED DOMAIN , 1992 .