Numerical Earth models - Earth Dynamics: Deformations and Oscillations of the Rotating Earth - page 522

Appendix C

Numerical Earth models

The inversion of seismological observations leads to the construction of models
of the physical properties of Earth. The basic models take Earth to be spheric-
ally symmetric with properties, such as density, the Lam´ecoe cients of elasticity,

and gravity, listed as functions of radius alone. These models form the numer-
ical basis for the calculation of Earth's dynamics, including its short-period and
long-period free oscillations, its response to tidal forcing and the dynamics of its
rotation.

C.1 The Earth models

We list here the files cal8.dat, 1066a.dat, prem.dat and core11.dat for four well-
known Earth models, Cal8 (Bullen and Bolt, 1985, pp. 471-473), 1066A (Gilbert
and Dziewonski, 1975), PREM (Dziewonski and Anderson, 1981) and Core11
(Widmer et al. , 1988), respectively. The first line in each case gives the name of
the Earth model in the format 10A8. The second line gives the number of Love
numbers to be calculated in the format I10. The third line gives the number of
model points and the initial number of integration steps for the inner core, outer
core, mantle and crust in the format 8I10. Although a variable stepsize Runge-
Kutta method is used in calculations, initial stepsizes are specified. The columns
tabulate the radius, density, the Lam´ecoe cients of elasticity, and gravity in the

format 1X,F10.1,F10.2,F10.1,F10.1,F10.1. Following tradition, radius is expressed
in kilometres, density in grams per cubic centimetre, the Lam´ecoe cients in kilo-

bars and gravity in centimetres per second per second. After they are read in, these
Earth properties are scaled to SI units before proceeding to calculations.