This program allows the generation of theoretical amplitudes and velocities for the Rayleigh and Love waves. The program calculates theoretical amplitudes and velocities for any layered model, for any frequency and any mode. This program will accept one liquid layer at the surface. In such case, the amplitudes of Rayleigh wave are that at the top of the solid array. For Love wave, the liquid layer is ignored. The method for the phase velocities computation is described in detail by Abo-Zena (1979). The group velocity is calculated from the phase velocity, by derivation of the phase velocity (Ben-Menahem and Singh, 1981). Finally, the amplitudes of the surface waves are computed according to Aki and Richards (1980). You can compute the theoretical amplitudes and velocities for the Rayleigh and Love waves by means of the present program, as it will be described below.

The LR program and its files are enclosed into a ZIP file named "LR.zip". When you have got the ZIP file and you have uncompressed this file, you have three files named

TMIN, TMAX, NT, LRVEL, LRAMP

NZ

THICK(1), ALPHA(1), SVEL(1), RHO(1)

THICK(2), ALPHA(2), SVEL(2), RHO(2)

...

...

...

THICK(NZ), ALPHA(NZ), SVEL(NZ), RHO(NZ)

The description of all parameters is as follows:

TMIN, TMAX, NT = Period range (in seconds) in which the computations will be performed. TMIN is the minimum and TMAX is the maximum of this interval. The maximum value for NT is 100.

LRVEL = With value 1 the phase velocities will be computed for the period interval given above. With value 2 the phase and group velocities will be computed.

LRAMP = With value 1 the surface wave amplitudes will be computed for the period interval given above. With value 0 the surface wave amplitudes will not be computed.

NZ = Number of layers of the earth model considered (maximum 100).

THICK(i), ALPHA(i), SVEL(i), RHO(i) = Thickness (km), P-wave velocity (km/s), S-wave velocity (km/s) and density (g/cm3); for the ith layer of the earth model considered. The NZ layer is the semi-infinite medium and its thickness must be given as zero.

The LR program can handle earth models with or without a liquid layer at the surface. Figure 1 and 2 show the phase and group velocities resulting for the sample file

With LRAMP = 1 the surface wave amplitudes are computed, for the period interval given in the input-data file

Figure 5 and 6 show the phase and group velocities resulting for the sample file

With LRAMP = 1 the surface wave amplitudes are computed, for the period interval given in the input-data file

Abo-Zena A. (1979).

Aki K. and Richards P. G. (1980).

Ben-Menahem A. and Singh S. J. (1981).