Application of teleseismic long-period surface waves from ambient noise in regional surface wave tomography: a case study in western USA

In this study, I investigate the feasibility of using teleseismic long-period surface waves from ambient noise in regional surface wave tomography and also evaluate the accuracy of long-period dispersion measurements at periods up to 150 s. About 300 USArray/Transportable Array (TA) stations located in the Colorado Plateau and surrounding areas and 400 teleseismic stations relative to the TA stations are selected. Clear, strong, and coherent long-period teleseismic surface waves at periods much longer than 50 s are observed in the teleseismic cross-correlations between the TA stations and the teleseismic stations. Using long-period dispersion curves from ambient noise, I generate phase velocity maps at 50-150 s periods and then compare them with phase velocity maps from teleseismic earthquake data. The results show that phase velocity maps from ambient noise data and earthquake data are similar at the 50-150 s period range, verifying the validity of using long-period surface wave from ambient noise in regional surface wave tomography.