Measuring Hazards Flashcards
Hot Spot
Volcanic regions thought to be fed by underlying mantle that is extremely hot compared with the surrounding mantle. They may be on, near to, or far from tectonic plate boundaries.
Magnitude
A measure of the size of an earthquake based on the quantity of energy released.
Mercalli Scale
A twelve-point scale for expressing the local intensity of an earthquake, ranging from I (virtually imperceptible) to XII (total destruction).
Moment Magnitude Scale
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.
Richter Scale
A numerical scale for expressing the magnitude of an earthquake on the basis of seismograph oscillations. The more destructive earthquakes typically have magnitudes between about 5.5 and 8.9.
Aseismic
Something not characterized by earthquake activity.
Seismic Waves
An elastic wave in the earth produced by an earthquake or other means.
Focal Depth
The depth below the Earth’s surface of the hypocentre of an earthquake.
Geothermal
Relating to or produced by the internal heat of the earth.
Parks Model
The extent to which earth hazards are predictable; the management strategies used to reduce the possible impact of a hazard; the effectiveness of managing earth hazards.
P Wave
A longitudinal earthquake wave that travels through the interior of the earth and is usually the first conspicuous wave to be recorded by a seismograph.
S Wave
A type of elastic wave, and are one of the two main types of elastic body waves, so named because they move through the body of an object, unlike surface waves.
Response Curve
A curve graphically exhibiting the magnitude of the response of a sensitive device to a varying stimulus.
Seismograph
An instrument that measures and records details of earthquakes, such as force and duration.
Volcanic Explosivity Index
A relative measure of the explosiveness of volcanic eruptions.
