Displacements, Velocities and Accelerations Converter
This program allows the conversion between time records of displacements, velocities
and accelerations, as it is described by Bath (1974). Thus, you can get time records of
accelerations or velocities from seismic records, accelerations or seismic records from
time records of velocities and velocities or seismic records from time records of
accelerations, as it will be described below (Corchete, 2010).
The AVD program and its files, which are needed to run this application, are enclosed
into a ZIP file named
When you have got the ZIP file and you have uncompressed this file, you have four files
named AVD.exe, series.dat, S408.dat and spectrum.dat.
The file AVD.exe contains a program (in FORTRAN code for PC) for the computation
of the conversion between time records of displacements, velocities and accelerations.
Running the program
Firstly, we need obtain the input file to be converted with the AVD program. For it, the
SERIES program can be very useful.
This program can be run with the input files: series.dat and S408.dat, which
are enclosed in the ZIP file named
AVD.zip. After that, the file displacement.dat
is generated and, then, we can run the AVD program using this file as input-data file.
When we run the AVD program the following menu is displayed:
1. Computation of accelerations and velocities from displacements.
2. Computation of accelerations and displacements from velocities.
3. Computation of velocities and displacements from accelerations.
... select the option (1,2,3):
Then, we can do each action shown in this menu entering the corresponding number.
If we select OPTION = 1, the program will compute the accelerations and velocities
from a time record of displacements. In this case, an ASCII file with the Fourier spectrum
of a time record of displacements, must be supplied. In this example, this input-data file
is supplied by the SERIES program, it is the file displacement.dat. Figure 1, shows
the amplitude spectrum contained in this file. After the computation, two new files have
been generated velocity.dat and acceleration.dat (also shown in Figure 1).
Fig. 1. Amplitude spectrum for the displacements, velocities and accelerations,
contained in the files displacement.dat, velocity.dat and
If we want to get the time records corresponding to these Fourier spectra, we can use
the SPECTRUM program with the option 0. After the
computation, three new files have been generated sd.dat, sv.dat and
sa.dat. These time records are shown in Figure 2.
Obviously, we can choose other options of the AVD
program to get accelerations and displacements from velocities or velocities and
displacements from accelerations. The computation process is in the same way, we need
to get previously the Fourier spectrum of the input time record, and after we can run
the programs AVD (to get the Fourier spectra) and SPECTRUM (to get the time records)
to get the converted time records. In all cases, the origin time of the input
time record is lost, because the Fourier spectrum has not information about it. For
this reason, this origin time must be added to the time scale of the output time records.
Fig. 2. Time records for the displacements, velocities and accelerations,
contained in the files sd.dat, sv.dat and
Bath M., 1974. Spectral analysis in Geophysics. Elsevier, Amsterdam.
Corchete V., 2010.
The analysis of accelerograms for the earthquake resistant
design of structures. International Journal of Geosciences, 2010, 32-37.