This site hosts a FORTRAN code called MINOS. This code lets you choose a
1D Earth model (card deck or polynomials) and a group of modes( e.g.
spheroidal fundamental, toroidal overtones, radial modes). The output
on the screen/ascii files are mode frequencies, attenuation, group
and phase velocities. A binary file contains the eigenfunctions
(U,U',V,V',W,W') for each mode, as a function of radius. With these,
you can calculate energy densities of a mode and sensitivity kernels
for a certain model parameter (e.g. Vp(r), rho(r)).
Play interactively on the Web:
Ruedi Widmer-Schnidrig made a web version of MINOS. You can choose between
4 models (1066a, 1066b, PREM, CORE11), calculate frequencies and plot energy
densities for any mode you like. play MINOS.
Examples
Here are some examples for energy densities for a few spheroidal modes.
The first example is for the first few fundamental modes
The second example is for the first few modes of the second overtone
branch
Note that the dashed line here is SHEAR ENERGY DENSITY. While in the interactive
version the dashed line is COMPRESSIONAL ENERGY DENSITY!
Download Source Code at CIG
we no longer support a direct local ftp link to MINOS.
But a good source to get MINOS is at Computational Infrastructure for
Geodynamics. The link below gets you there. If you are only interested
in computing normal mode frequencies and eigenfunctions, you do not need
the whole package. You only need minos_bran which is described in
the MINEOS documentation, Chapter 3.1. Minos_bran is an updated version
of MINOS that used to be available on the local ftp site. All the other
tools included in the CIG package allow you to compute Green's Functions,
and ultimately synthetic seismograms.
Woodhouse, J.H., The Calculation of Eigenfrequencies and Eigenfunctions
of the Free Oscillations of the Earth and the Sun, 1988. in:
D.J. Doornbos (ed.) "Seismological Algorithms, Computational Methods and
Computer Programs", Academic Press, London, UK, 321-370.
Guy's class notes
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Gabi Laske ( glaske@ucsd.edu)
