S. Husen et E. Kissling, Local earthquake tomography between rays and waves: fat ray tomography (vol 123, pg 127, 2000), PHYS E PLAN, 125(1-4), 2001, pp. 169
The limitations of ray-based forward solutions in seismic tomography are th
eoretically well known. To correctly represent the physical forward problem
in seismic tomography, application of full three-dimensional (3-D) wave th
eory would be required. Up to now this is not possible for the size of a ty
pical local earthquake study. With the concept of fat rays resembling the w
aves Fresnel volume, a more complete, physically consistent and accurate so
lution to the forward problem is available. In this paper, we present an ap
proach to include fat rays in local earthquake tomography, called Fatomo. T
he comparative study with synthetic data and inversion results with Fatomo
and a ray-based approach to local earthquake tomography, SIMULPS, reveals n
ew insights into the role of resolution and model parameterization in local
earthquake tomography. Intuitively expected effects of fat rays on resolut
ion estimates, such as higher node sampling values and lower resolution dia
gonal element values for wider fat rays can be seen in the results. For ide
al model parameterization, differences between fat ray and ray tomography a
re small. Our results document, however, that the influence of model parame
terization is less critical for fat ray tomography than for ray tomography.
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