Included here is a variety of
information about our studies of the Earth's low frequency normal modes.
The information is intended mostly for other seismologists and geodynamicists
who would like to use the normal mode structure coefficients in inversions
for the spherical and/or aspherical elastic and/or anelastic structure
of the deep Earth. Some introductory information can be found by clicking
the following: 1, 2,
The main point is that normal
mode structure or interaction coefficients place strong constraints on
the spherical and aspherical structure of the deep Earth. To date, their
use has been rare in inversions for global models. However, recent advances
have greatly increased their number and improved their reliability and
the accuracy of the coefficient uncertainties. In addition, normal mode
constraints up through and beyond degree 8 are now common and there are
now constraints on odd-degree Earth structures. These factors in combination
imply that the recent tabulations of structure coefficients should provide
a powerful tool to investigate the deep structure of the Earth.
Like geoid coefficients, normal
mode structure coefficients are quite transportable and should be able
to be utilized in a wide variety of applications concerning the deep Earth.
We will make an attempt to provide the necessary information, e.g., integral
sensitivity kernels and related information, to facilitate use by other
researchers. This information will be developing with time.
To date, we have concentrated
efforts on the low frequency spectrum below 3 mHz and have estimated self-coupled
and cross-coupled structure coefficients for about 90 multiplets. It is
our plan to continue to apply the method to many more multiplets above
Plots of even degree structure
coefficient estimates and uncertainties and comparison to predictions from
existing models, splitting function plots, integral sensitivity kernel
plots are provided as a function of the normal mode branch: 0S, 1S, 2S,
3S, 4S, 5S, 6S, 7S, 8S, 0T, 1T, 2T, 3T, 4T. Plots of cross-coupled coefficient
estimates, etc. are also provided. Tables of coefficients, uncertainties,
and kernels are also provided, segregated by degree, on the main page.
If you have
questions, comments or suggestions, email Mike Ritzwoller at email@example.com
to Normal Mode Seismology Research Page.
to Geophysics Group Home Page.