Fj. Esparza et E. Gomeztrevino, IMPLICATIONS OF SPATIAL-FILTERING ON THE RESOLVING POWER OF MAGNETOTELLURIC DATA, Physics of the earth and planetary interiors, 99(1-2), 1997, pp. 113-119
The interpretation of magnetotelluric data, using either inverse metho
ds or data-filtering techniques, is underlain by the fundamental quest
ion of how can surface measurements be combined to best estimate the u
nderground resistivity distribution. Existing methods differ from each
other in that they apply different combination rules. Deciding what i
s optimal necessarily requires a common ground for comparison. In term
s of the simplest case: What is the difference between st standard mag
netotelluric measurement and a spatially filtered datum? Can they be c
ompared? Our approach to the problem is to represent individual measur
ements as weighted averages of the underground resistivity distributio
n. Applying this representation to linear combinations of measurements
allows a direct comparison between processed and unprocessed data. Th
e analysis is further extended to include two-dimensional Backus-Gilbe
rt resolving kernels for both types of data. Our results indicate that
spatial filtering introduces a focusing effect that greatly improves
the resolution at depth.