Glossary

The fault distance (R_F) is one of the measures of the source-site distance currently used in the engineering and seismology applications. It is defined as the minimum distance between the observation point and the earthquake fault.

Vertices of the Fault Plane projection on the Earth's surface

An earthquake occurs when a volume of rock, subject to deformation mechanisms of tectonic origin, breaks along a weak surface, which is denoted as fault, resulting in a relative displacement between the two blocks of rock separated by the fault plane.

The brittle result of a fault that ruptures the ground-surface.

The uncorrected records collected by the recording instrument are generally processed for the following purposes:

The focal mechanism represents the geometry of fault rupture during an earthquake (see Fault Plane).

The underlying side of a non-vertical fault surface.

A free-field record is a record of seismic ground motion, obtained at a sufficient distance from near-by structures, so that its response is not altered significantly in a wide frequency range, indicatively between 0 and 20 Hz. The instrument location (see Housing) should minimize the interaction effect with the host structure or adjacent structures.