ZDF analysis facilities for 3-component data:
for arrival time residual estimation and array beamforming.
for tracking phases comprising any number of reflection and transmission branches in complex layered media. Uses fast marching to compute traveltimes, and can also generate raypaths and Frechet derivatives.
for mapping relative arrival time residuals as 3-D variations in wavespeed beneath a seismic array.
for mapping traveltime residuals as 2-D variations in wavespeed.
for mapping a variety of traveltime datasets (e.g. local earthquake, teleseismic, reflection, wide-angle) as 3-D variations in seismic wavespeed and interface structure. Sources may also be relocated.
Fortran77 program for relocating earthquakes with the double-difference algorithm of Waldhauser and Ellsworth (2000). On SUN Solaris 10 x86 only with command: hypoDD
Traditional methods of seismic tomography represent structure in terms of regular grids or truncated Fourier series, both of which may be inconsistent with the inhomogeneous distribution of data that characterizes most seismic surveys. In such circumstances, the extraction of structural information from the data is not maximized. With an inhomogeneous distribution of data, the minimum wavelength of structure that can be resolved varies both spatially and directionally; only an irregular parameterization is capable of capturing such information.
We simultaneously invert for 1-D P and S-velocity models inside each tectonic region of Earth, each defined with by iregular 3-D parameterization. A description of the RUM project with figures and results can be found here.
Earthquake Risk Model (EQRM) is capable of earthquake scenario ground motion and scenario loss modelling as well as probabilistic seismic hazard (PSHA) and risk (PSRA) modelling. Download the publication.
A computer program to compute regolith site-response and estimate uncertainty for probabilistic seismic hazard analyses. Download the publication.