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High Resolution Shallow Previous HitCrustalNext Hit Imaging Using Passive Seismic Dense Arrays


The recent development on passive seismic imaging methods combined with the availability of dense seismic arrays has now opened up many new opportunities on high-resolution shallow Previous HitcrustalNext Hit imaging. Seismic interferometry and tomography, for example, has been used to extract seismic waves propagating between stations and invert for 3D Previous HitcrustalNext Hit Previous HitstructureNext Hit. Receiver function analysis, on the other hand, has been used to investigate dominant Previous HitstructureNext Hit discontinuities such as the sediment/bedrock interface. In this presentation, I will review the work our group has done on using these methods to image shallow hydrothermal, geothermal, sedimentary, and fault zone Previous HitstructureNext Hit. In each study, hundreds to thousands of autonomous geophones were deployed and recorded passive seismic signals continuously for up to 35 days. By calculating the cross-correlations between all the background seismic noise recorded, we can extract surface wave signals that are sensitive to Previous HitstructureNext Hit from surface down to couple kilometer depth. Applying the method to the data collected within the Upper Geyser Basin in Yellowstone, for example, has revealed the hydrothermal reservoir of Old Faithful geyser between 20 and 60 meter depth. Similar method has also been used to construct a 3D Previous HitcrustalNext Hit velocity model in Long Beach, California, and the model was used to make static correction for the active source experiment. With three-component data, receiver function analysis can be done using teleseismic signals and multi-component deconvolution. With a dense station coverage, coherent shallow Previous HitcrustalNext Hit interfaces can be tracked and local geology can be interpreted. For example, we observed clear basement dipping at the FORGE geothermal site near Milford, Utah. The ability to image shallow Previous HitcrustalNext Hit Previous HitstructureTop using passive signals now provides a new way to explore near surface geology with a much reduced cost.