Taking advantage of the similarity of long period S and P waveforms, we have developed a method of identifying phase arrival times that combines the speed of automated methods with the quality control capabilities of manual methods. The method groups seismic phases based on their cross-correlation coefficients and is referred to as "cluster analysis". The bottom figure shows one of the windows of this analysis where the traces (right, here S waves) are color-coded according to their level of cross-correlation (cluster tree, left). The resulting arrival time picks are used to invert for shear and compressional velocities models. These are shown in 3D below.
HMSL = Houser, Masters, Shearer, Laske : S = Shear: P= Compressional: 06 = 2006
This work is published in GJI.
Below click on the "hsml.s.dat.gz" and "hmsl.p.dat.gz" to download the model files. They are zipped and formatted as a 4 degree grid:
longitude, latitude, depth, value
The mean has not been removed so that will have to be done before viewing the models.
HMSL - S06
HMSL - P06
Cluster Analysis