... earthquake tomography with double-difference tomography code using catalog differential time data. In this paper, Simulps14 code on the same data set is applied. For better approach P arrival time and S-P travel times are inverted directly for Vp, Vp/Vs variations and earthquake locations. High Vp ∼5.9...

... locations. In SIMULPS14, seismic velocities are defined at grid nodes of intersecting lines in x -, y -, and z -directions. Line spacing can be irregular to compensate for uneven ray distribution. In local earthquake tomography, the parameterization of the 3D model should be chosen to guarantee uniform...

... version of this figure is available only in the electronic edition. With the new 3D models, we have relocated, using SIMULPS14, the pool of 232,856 events previously described, and compared the 3D locations with those refined with the double‐difference approach ( Waldhauser et al. , 2021 ). The 3D...

... × 5 × 3 km x - y - z grid, obtained based on the optimization of model resolution and image fidelity, with the Simulps14 code ( Haslinger, 1998 ). The velocity model was continuously defined in space from interpolation of node-grid values that were iteratively perturbed from the initial values until...

... method, which we call Bayloc, with a classical, least-squares, linearized location method ( llsq ) in 3D velocity models. We extracted the llsq algorithm for earthquake location from the Simulps14 simultaneous inversion procedure by Eberhart-Phillips (1993) . Such a location algorithm solves...

.... To define the model resolution, we computed synthetic tests, creating a velocity model, and compared the model reproducibility with the spread function (SF) computed by means of Simulps14 (as defined in Toomey and Foulger, 1989 ). We fixed a value of SF = 2, indicative of compact averaging vectors...

... grid with 5 km horizontal and 3 km vertical spacing. It was developed by Chiarabba et al. (2018) by inverting P and S travel times from regional aftershocks using the code Simulps14 ( Haslinger, 1998 ). The travel‐time data used in the inversion included ∼44,000 readings from aftershocks...