Glossary

Instrument to measure seismic acceleration

An active fault is a fault that has slipped during the present seismotectonic regime and is therefore likely to have renewed displacement in the future.

A ground-motion parameter derived from an accelerogram and proportional to the integral of the acceleration squared over the entire signal duration.

An event or process detected by geological/geophysical tools and analyses that is apparently not accompanied by earthquake activity.

In general a direction measured clock-wise in degrees against the North.

The direction from the seismic station towards a seismic source, usually measured in degrees clock-wise from North.

A range between high-pass and low-pass cut-off frequencies.

Baseline correction is a procedure to correct certain types of long period disturbances on accelerometric signals

Relatively hard

An event or process detected by geological/geophysical tools and analyses that is directly associated with earthquake activity.

The depth range that includes the location of the causative (i.e. seismogenic) fault of an earthquake – either a particular one or an expected/forecasted one – within the crust (or below depending on cases).

Inclination of the fault plane from the Earth's surface (measured in degrees)

Duration is defined as the time interval of the accelerometric signal in which the seismic motion is significant.

The seismic site classification is based on the stratigraphic and dynamic properties of the soil profile. Site classes are defined according to the Eurocode 8 as follows:

The epicentral distance is defined as the distance on the ground surface between the site and the earthquake epicenter.