Glossary

Amplitude - approximately the maximum height of the wave above sea level when in deep water. Note that this is not the same as the "double amplitude" which is the vertical distance between the crest and the trough and is often used to describe the height of a wave.

Egress - the action of going out of or leaving a place.

Epicenter - The point on the Earth's surface directly above the focus.

Fault scarp - a small step or offset on the ground surface where one side of a fault has moved vertically with respect to the other.

Focus or hypocenter - The area of the fault where the sudden rupture takes place.

Inundation – the result of a tsunami traveling a long distance inland and is a horizontal measurement of the path of the tsunami.

Intensity- based on the observed effects of ground shaking on people, buildings, and natural features. It varies from place to place within the disturbed region depending on the location of the observer with respect to the earthquake epicenter.

Landing - the horizontal platform at the end of a stair flight or between two flights of stairs

Magnitude - related to the amount of seismic energy released at the hypocenter of the earthquake. The magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs.

Moment Magnitude Scale - The moment magnitude scale (abbreviated as MMS; denoted as Mw or M) is used by seismologists to measure the size of earthquakes in terms of the energy released. The scale was developed in the 1970s to succeed the 1930s-era Richter magnitude scale (ML).

Occupant load - maximum capacity/occupancy which is often based on means of egress (exit or entrance)

Richter scale - developed in 1935 by Charles F. Richter of the California Institute of Technology as a mathematical device to compare the size of earthquakes.

Run-up height/elevation - measured at the maximum run-up above the normal ocean level at the tsunami time frame.

Run-up distance - the maximum distance from the tide or shoreline at the time of the tsunami

Run-up factor - the deep-water wave amplitude divided by the run-up height.

Shear – to break off or cause to break off

Shear strength - degree to which a material or bond can resist shear

Stair - a series of steps, or flights of steps, connected by landings, which permits passage between two or more levels or floors

Stairway or staircase - a flight of stairs, or a series of such flights, including supports, handrails, and framework; the structure containing a flight of stairs

Stair string or stringer - an inclined member which supports the steps

Stairwell or stair core - a vertical shaft containing a stairway

Seismic - relating to earthquakes or other vibrations of the earth and its crust

Topography – a detailed description or representation on a map of the natural and artificial features of an area

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