The database contains a large number of records of seismic accelerations measured at the ground level during earthquakes with magnitudes M > 5. Besides the actual acceleration records (all stored in an unique format and units system) and information on the earthquake events, each record contains information on the site geology and local soil conditions.
PRISM allows the user to search the database for records (using various search criteria), display/print the search results, and retrieve the desired acceleration time histories. As more information becomes available to the user, new records can be easily added from other databases and old records can be updated.
Aside from providing access to the database, PRISM has other helpful utilities. A package of tools allows the user to transform each acceleration record (i.e. to obtain displacement and velocity time histories, Fourier transforms and response spectra, and to filter the acceleration time history). These results can also be retrieved, plotted and printed.
A procedure for digital generation of non-stationary stochastic processes, capable of simulating seismic ground motion time histories (accelerations or displacements) that: (1) are compatible with prescribed response spectra, (2) have prescribed modulating functions to control the duration of the strong motion, and (3) are correlated according to a given coherence function, including the wave propagation effect, is also available.
PRISM has a friendly user interface, written in C and using the OSF Motif toolkit, for the UNIX operating system.