Glossary
| There are many scientists that have contributed to our understanding of the earth . The language of the geologist grows with our understandings of the earth. Some of the words used have been around for hundreds of years. The term 'plate tectonics', for example, is a new term to be understood within the context of old words. To cite back to the origin of terms and understanding is not the purpose of this web site. Though, current authors and publishers are cited and new terms are explained.
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Crust
What we know of as land, rocks and the like. The outer most layer of the earth. Continential crust is mostly granite and granodiorite, while the crust under the ocean is mostly basalt.
Earthquake ('quake')
Movement of the earth's crust along a fault. You may feel a shake, bounce, vibration or swaying motion.
Experiment
A test or trial taken to demonstrate or discover something. (
Webster's
, 1990)
Fault
A fracture of the earth's crust, where there has been movement between two blocks of crust. Where the edges of the bricks meet during the experiment on page one of the
'Earthquake Hazards' website.
Force
Force is that which changes the state of rest or motion of a body. Strength; power,'energy' that causes or alters motion. "Body forces, and contact forces created through loading, are ultimately responsible for geologic deformation. These forces work through the 'undercover agent' known as stress."(
Davis
, G. H. and Reynolds, S. J.,1996.)
Geology
The science of the Earth that deals with the origin, evolution and composition of the planet. The study of rocks is geology. The study of the ocean floor is also geology. Geophysics, seismology and geochemistry are also studies of geology.
Lithosphere
The outer shell of the earth. The crust plus part of the upper mantle make up the lithosphere.
Magnitude
The strength or power of an earthquake. A magnitude 5 is ten times larger than a magnitude 4. A magnitude 4 is ten times larger than a magnitude 3 and so on respectively."A measure of earthquake size, determined by taking the common logarithm (base 10) of the largest ground motion observed during the arrival of a P wave or seismic surface wave and applying a standard correction for distance to the epicenter."(
Press/Seiver
,2001)
Plate Tectonics
The theory and study of plate formation, movement and interactions. Earthquakes, the origin of mountains and valleys, volcanos and almost all aspects of geology involve the theory of plate tectonics.
Pressure
Amount of force divided by the area the force is applied to. Example, a pail of water sitting in the sand applies pressure to the sand beneath the bottom of the pail. The 'pail' of water is 'force' and the bottom of the pail is 'area'. Place the pail on top of a soda pop can and the can on top of the sand. The area of the can's bottom is smaller so the pressure is greater and the sand is left with a deeper impression from the same force.
Seismology
The science dealing with earthquakes. (
Webster's
, 1990)
Stress
The force exerted when one body presses, pulls or pushs against another body. Like the plate experiment on page two, and the brick experiment on page one of the
'Earthqake Hazards'
website.
Thrust Fault ('thrust')
Thrust faults, also know as reverse faults are caused by compressional force. Like the plate experimnet on page two of the
'Earthquake Hazards' website. "Thrust, tectonic structure that is a low angle or reversr fault." (
Oxford
, 1985)
Tectonics
"Said of or pertaining to the force's involved in, or the resulting structures or fractures of, tectonics" (
Bates and Jackson
, 1980)
This page was updated March 13, 2002