GOALI: Seismic interferometry and reflection imaging of the deep crust

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The proposed research aims to merge methods of academic passive source seismology with industry active source seismology for enhanced subsurface seismic imaging at a variety of scales. The emerging methods of seismic interferometry will be explored and applied. Work on the proposed project will be used to improve corrections for near-surface variations, develop schemes for incorporating virtual source methods into seismic reflection imaging, and to further utilize seismic data sets collected in the past. Methods will be applied both to sedimentary basins of economic interest and to deep Rocky Mountain fault systems, with implications for crustal deformation processes and origin of the deep structures that formed the Rocky Mountains. The collaboration with industry will benefit the project through access to computer hardware and software, and to industry signal processing and large data set expertise.In this project the utility of including virtual source gathers and velocity structures derived from interferometry in seismic reflection studies will be explored. The two main approaches that will be followed include development and comparison of near-surface statics corrections derived from surface wave ambient noise tomography to those from traditional refraction statics, and active source interferometry applied to reflection surveys. Rather than restricting the interferometry to ambient background noise, the virtual source methods take advantage of waveform recordings of signals such as active source blasts, mine blasts, and distant and local earthquakes. The study will utilize a modern data set from a combined active-passive seismic experiment (Bighorn Arch Seismic Experiment or BASE), and a 1970?s era vibroseis data set (COCORP Wind River mountains experiment). The main geologic targets in each case are the deep faults beneath the Laramide Arches and flanking basement, including suggested crustal detachment features widely invoked in structural models. The proposed contributions will be of general use beyond this particular geologic environment and geographic province, and will more fully exploit existing data sets. A comparison of resulting images from this proposed study can provide an opportunity to evaluate the effectiveness of each imaging method with diverse data sets, and the accompanying active source experiments provide an important check on results.