California
PmP phase identification using waveform stacking method (Richards-Dinger & Shearer, 1997)
By stacking waveforms within reflection point bins, it is possible to measure the U-shape curve, i.e., the PmP-first P differential traveltimes with respect to distances. Then the U-shape curves can be fitted with two free parameters: Moho depth and P-wave velocity in the uppermost mantle.
Technical workflow:
Aligning the collected event waveforms to the first-P arrivals;
Based on regional 1D HK model (Hadley & Kanamori, 1977), conducting the focal depth correction to the aligned waveforms, making the PmP arrivals solely dependent on the epicentral distances;
Binning the waveforms based on the reflection points;
Stacking the waveforms within each bin to enhance the PmP signals;
Measuring the differential traveltimes and fitting the U-shape curves to estimate the Moho depth and P-wave velocity in the uppermost mantle.
Results of Moho depth and uppermost mantle P-wave velocity estimation in Southern California:
