The spectral ratio method is used to conduct Q analysis with synthetic VSP and reflection data. Testing results show that the spectral method can deal with frequency independent energy loss including geometric spreading and transmission loss, and can also be used to derive the layered Q structure of subsurface. For real data, the notches in spectrum, due to reflectivity, are a severe problem for spectral ratio calculation. The adaptive multitaper method for spectral estimation is shown to give a smooth estimate with little evidence of notching, and is superior to both DFT and Burg spectral estimates.
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