Home CDEMA

Share |

Glossary

Search for glossary terms (regular expression allowed)
Begins with Contains Exact term Sounds like
All A B C D E H I L M O P R S T W
Page:  « Prev 1 2 3 4 5... Next »
Term Definition
Intensity

A measure of an earthquake's extreme strength, force, energy or effects at specific locations. The most commonly-used scale of intensity is the Modified Mercalli Intensity (MMI) index, which defines a range from one to twelve (I to XII), with one being the lowest and XII the highest intensity.

Inundation

The horizontal distance inland that a tsunami penetrates, generally measured perpendicularly to the shoreline.

Inundation (Maximum)

Maximum horizontal penetration of the tsunami from the shoreline. A maximum inundation is measured for each different coast or harbour affected by the tsunami.

Inundation Area

Area flooded with water by the tsunami.

Inundation Line

Inland limit of wetting, measured horizontally from the mean sea level (MSL) line. The line between living and dead vegetation is sometimes used as a reference. In tsunami science, the landward limit of tsunami run up.

Leading Wave

First arriving wave of a tsunami. In some cases, the leading wave produces an initial depression or drop in sea level, and in other cases, an elevation or rise in sea level. When a drop in sea level occurs, sea level recession is observed.

Local Tsunami

A tsunami from a nearby source for which its destructive effects are confined to coasts within 100 km of the source (or, alternatively, less than 1 hour travel tsunami travel time). A local tsunami is usually generated by an earthquake, but can also be caused by a landslide or a pyroclastic flow from a volcanic eruption.

Magnitude

Related to the amount of energy released during an earthquake. It is determined from parameters of the seismic waves recorded on seismographs e.g. amplitude, period, duration. A magnitude of 7.0 on the Richter Scale is a major earthquake. Each whole number on the scale represents an increase of about 10 times more energy released than the previous whole number represents. Therefore, an earthquake measuring 7.0 is about 100 times more powerful than one measuring 5.0.

Mangrove Forest

A community of salt-tolerant trees and shrubs, with many other associated organisms that grows on some tropical and sub-tropical coasts in a zone roughly coinciding with the intertidal zone.

Mean Height

Average height of a tsunami measured from the trough to the crest after removing the tidal variation.

Mean High Water (MHW)

The average height of the high water over a 19-year period. For shorter periods of observations, corrections are applied to eliminate known variations and reduce the results to the equivalent of a mean 19-year value. All high water heights are included in the average where the type of tide is either semi-diurnal or mixed.

Mean Low Water (MLW)

The average height of the low water over a 19-year period. For shorter periods of observations, corrections are applied to eliminate known variations and reduce the results to the equivalent of a mean 19-year value. All low water heights are included in the average where the type of tide is either semi-diurnal or mixed.

Mean Sea Level (MSL)

The average height of the surface of the sea for all stages of the tide over a 19-year period, usually determined from hourly height readings. Not necessarily equal to mean tide level. It is also the average water level that would exist in the absence of tides.

Mean Tide Level

A plane midway between mean high water and mean low water. Not necessarily equal to mean sea level. Also referred to as half-tide level.

Ocean Wide Tsunami

A tsunami capable of widespread destruction, not only in the immediate region of its generation but across an entire ocean. All ocean-wide tsunamis have been generated by major earthquakes. Synonym for tele-tsunami or distant tsunami.

Page:  « Prev 1 2 3 4 5... Next »
All A B C D E H I L M O P R S T W
Back To Top
CDEMA USAID European Union Home Project Management Glossary Links Contact Us
Credits/Copyrights Sitemap Disclaimer
Acute Vision Incorporated