Terminology:

Throughout our explanations and analysis of the various disasters and responses we have strived to use as accurate and scientific terminology as possible. Accordingly, you may not be familiar with some of these very technical words. Please use this glossary to learn more about certain concepts or terms you found in the site, or click highlighted words within the content.

A
Absorption rates
The mathematical rate at which soil absorbs water. This ratio is significant because a lower rate indicates greater water runoff and the potential for flooding.
Acid
A descriptive term applied to igneous rocks with more than 60% silica (SiO2).
Active Volcano
A volcano that is erupting. Also, a volcano that is not presently erupting, but that has erupted within historical time and is considered likely to do so in the future.
Advisory
Official information issued by tropical cyclone warning centers describing all tropical cyclone watches and warnings in effect along with details concerning tropical cyclone locations, intensity and movement, and precautions that should be taken.
Agricultural drought
This type of drought is caused when there is not enough moisture for crop production. It can be created due to both soil conditions and human land development techniques.
Allies
Organizations or other countries to which a primary country is associated with. Allied associations generally entail some sort of reciprocal military protection and economic trade benefits.
AIDS
Acquired immunodeficiency syndrome is a collection of symptoms and infections resulting from the specific damage to the immune system caused by infection with the human immunodeficiency virus (HIV). It results from the latter stages of advanced HIV infection in humans, thereby leaving compromised individuals prone to opportunistic infections and tumors. Although treatments for both AIDS and HIV exist to slow the virus' progression in a human patient, there is no known cure.
Airport 'locks'
The government based shutting down of an airport for security reasons.
Alkalic
Rocks which contain above average amounts of sodium and/or potassium for the group of rocks for which it belongs. For example, the basalts of the capping stage of Hawaiian volcanoes are alkalic. They contain more sodium and/or potassium than the shield-building basalts that make the bulk of the volcano.
Amplitudes
The maximum vertical displacement of a periodic wave.
Anemometer
A device used to measure wind speed.
Anthropogenic
The influence of humans on natural elements. Many feel such action is degrading unto the land.
Ash
Fine particles of pulverized rock blown from an explosion vent. Measuring less than 1/10 inch in diameter, ash may be either solid or molten when first erupted. By far the most common variety is vitric ash (glassy particles formed by gas bubbles bursting through liquid magma).
Ash fall (Airfall)
Volcanic ash that has fallen through the air from an eruption cloud. A deposit so formed is usually well sorted and layered.
Ash Flow
A turbulent mixture of gas and rock fragments, most of which are ash-sized particles, ejected violently from a crater or fissure. The mass of pyroclastics is normally of very high temperature and moves rapidly down the slopes or even along a level surface.
Atlantic Thermohaline Circulatory Body
This type of circulation system is that which is driven by differences in relative density and temperature. The salinity and temperature differences arise from heating and cooling at sea surfaces and from the surface freshwater evaporation and precipitation. Specifically in the Atlantic circulatory body, the water is labeled as a deep current system.
B
Barometer
A device used to determine air pressure of the atmosphere.
Basalt
Volcanic rock (or lava) that characteristically is dark in color, contains 45% to 54% silica, and generally is rich in iron and magnesium.
Basic
A descriptive term applied to igneous rocks (basalt and gabbro) with silica (SiO2) between 44% and 52%.
Bourgeoisie
The French Revolutionary term for working class civilians.
C
Caldera
The Spanish word for cauldron, a basin-shaped volcanic depression; by definition, at least a mile in diameter. Such large depressions are typically formed by the subsidence of volcanoes. Crater Lake occupies the best-known caldera in the Cascades.
Cape Verde Storm
A tropical cyclone or storm that originates near the Cape Verde Islands in the Atlantic. Cape Verde storms are generally long lasting and usually quite strong. Hurricane Ivan of 2004 was a classic example of a Cape Verde Storm.
Center of Circulation
The center of the storm, also called the eye in hurricanes.
Channels
A course or pathway through which water flows, either by natural or synthetic means. Rivers, for example, are channels. However, people could always cut a deep pathway from a lake to a village and the water route would be a channel.
Cholera
Cholera (also called Asiatic cholera) is an infectious disease of the gastrointestinal tract caused by the Vibrio cholerae bacterium. These bacteria are typically ingested by drinking water contaminated by improper sanitation or by eating improperly cooked fish, especially shellfish. Symptoms include diarrhea, abdominal cramps, nausea, vomiting, and dehydration. Death is generally due to the dehydration caused by the illness.
Cinder Cone
A volcanic cone built entirely of loose fragmented material (pyroclastics).
Civilization
A developed and advanced state of human matters in society. Such an entitlement is characterized by technical advancement in the sciences and extensive progress in political matters, even through self-governance.
Civil war
War occurring between at least two different organizations within a country, generally vying for political control. These wars are generally very brutal and devastating as they can pit family members against one another and leave no man safe from another.
Composite Volcano
A steep volcanic cone built by both lava flows and pyroclastic eruptions.
Compound Volcano
A volcano that consists of a complex of two or more vents, or volcano that has an associated volcanic dome, either in its crater or on its flanks. Examples are Vesuvius and Mont Pelee.
Continental Crust
Solid, outer layers of the earth, including the rocks of the continents. Usage of continental crust.
Continental Drift
The theory that horizontal movement of the earth's surface causes slow, relative movements of the continents toward or away from one another.
Convection
The heavy thunderstorms and high cloud tops associated with a tropical system. Also, the transfer of heat in a gas or liquid setting through the circulation of currents from one region to another. In geographic terms, this occurs through the movements of well-established wind currents.
Convention on the Prevention and Punishment of the Crime of Genocide (CPPCG)
A convention adopted by the UN General Assembly in December 1948 and came into effect in January 1951. It defines and outlaws genocide, as a result of campaigning by Raphael Lemkin who had coined the term some years earlier. The total number of states who have ratified the convention is currently 137.
Coriolis effect
The deflective effect of the earth's rotation on all free-moving objects, including the atmosphere and oceans. To the right in the northern hemisphere and left in the southern hemisphere.
Curtain of Fire
A row of coalescing lava fountains along a fissure; a typical feature of a Hawaiian-type eruption.
Cyclones
Another name for a hurricane, primarily used in the Indian and South Pacific Oceans.
Cyclonic storm
wind storm with clockwise rotating winds formed through the meeting of sweeping bits of warmer air and the cooler jet stream air
D
Deforestation
The removal of natural forest areas for urban development projects. This action though, can also occur through forest fires, which incidentally destroy significant natural elements.
Doppler radar
A weather radar system that uses the apparent shift in frequency of radio waves (Doppler effect) to discern air motion and accordingly predict tornadoes and precipitation courses very expeditiously, as well as measure the speed and direction of rain and ice.
Dormant Volcano
Literally, "sleeping." The term is used to describe a volcano which is presently inactive but which may erupt again. Most of the major Cascade volcanoes are believed to be dormant rather than extinct.
E
Earthquake
An abrupt movement of the earth’s plates.
Elastic-Rebound theory
The sudden release of the strains that accrue at plate boundaries on the Earth’s lithosphere.
Electromagnetic pulse (EMP)
A pulsation of very strong electrically based radiation created by a unique set of occurrences. Tests and studies prove that nuclear explosions generate significant electromagnetic pulses, with radiation powerful enough to disable communication devices.
Epicenter
The point on the earth’s surface directly above the hypocenter.
Eroding
The mechanical process of grinding and breaking down natural objects by running water or wind. Over thousands and millions of years, running water and wind have channeled such features as the Grand Canyon in the United States.
Eruption
The process by which solid, liquid, and gaseous materials are ejected into the earth's atmosphere and onto the earth's surface by volcanic activity. Eruptions range from the quiet overflow of liquid rock to the tremendously violent expulsion of pyroclastics.
Eruptive Vent
The opening through which volcanic material is emitted.
Extinct Volcano
A volcano that is not presently erupting and is not likely to do so for a very long time in the future.
Extrusion
The emission of magmatic material at the earth's surface. Also, the structure or form produced by the process (e.g., a lava flow, volcanic dome, or certain pyroclastic rocks).
Extratropical
A term used to describe a formerly tropical storm or hurricane that has lost its tropical characteristics. Extratropical storms can still be powerful, but no longer possess a warm core and other tropical characteristics.
Eye
The center of a hurricane, usually not found in tropical storms. The eye is usually calm and sometimes cloudless.
Eyewall
The most powerful part of the storm that surrounds the eye. The highest winds, heaviest rains, and strongest storms are found here.
F
Fault
A crack or fracture in the earth's surface. Movement along the fault can cause earthquakes or, in the process of mountain-building can release underlying magma and permit it to rise to the surface.
Fission
A nuclear reaction where the nucleus of an atom, splits into fragments of similar mass, releasing several hundred million electron volts of energy. This is one of the most powerful energy sources.
Fujita
Pearson Tornado Scale-the Tornado intensity scale measures tornados on a level from F0 (lowest) to F5 (highest) based on wind speed and damage potential.
Funnel cloud
This situation is the characteristic image of tornados as the densely swirling mass of wind shaped like a funnel. The situation arises because the wind system has generated a strong enough wind velocity.
Fusion
A nuclear reaction where separate nuclei combine, forming a larger nuclei through the concurrent release of energy.
G
Geothermal Energy
Energy derived from the internal heat of the earth.
Greenhouse Effect
The process in which green house gases, like carbon dioxide in the Earth's atmosphere, cause thermal radiation emitted by the Earth's surface to be reflected back down, therefore causing the climate to warm. This natural process is enhanced by man's added pollutants and can reach proportions at which a number of animal and plant species can be threatened with extinction, not to mention cause drastic changes in the Earth's natural weather patterns.
Gross Domestic Product
The total dollar value of all goods produced by citizens of a country, regardless of their location. This measure reveals the aggregate success and power of a particular country’s economy.
H
Herbicides
A chemically based substance used to stem plant growth. Humans, creating discussion as to their practicality, can also inhale such chemicals.
HIV
Human immunodeficiency virus. A virus that steadily weakens the body's defense (immune) system until it can no longer fight off infections such as pneumonia, diarrhea, tumors and other illnesses. All of which can be part of AIDS (Acquired ImmunoDeficiency Syndrome). Unable to fight back, most people die within three years of the first signs of AIDS appearing.
Hot Spot
A volcanic center, 60 to 120 miles (100 to 200 km) across and persistent for at least a few tens of million of years, that is thought to be the surface expression of a persistent rising plume of hot mantle material. Hot spots are not linked to arcs and may not be associated with ocean ridges.
Hot-spot Volcanoes
Volcanoes related to a persistent heat source in the mantle.
Hurricane
A tropical cyclone with winds greater than 73 mph. This name is used in the Atlantic and East Pacific Basins.
Hurricane Season
The time when most hurricanes form, lasting from June 1 to November 30 in the Atlantic Basin, and May 15 to November 30 in the East Pacific Basin. Keep in mind that many storms form out of these boundaries.
Hurricane Watch
An announcement stating that hurricane force conditions are possible within 36 hours in the watch area.
Hurricane Warning
An announcement stating that hurricane conditions are expected in the warning area within 24 hours or less.
Hydrologic drought
This type of drought occurs when water reserves in sources such as lakes and reservoirs fall below their statistical average. Even in times of above average precipitation, this it can occur when increase water usage diminishes the amount of water in reserves. In the context of urban planning, this type of drought is most considered.
Hypocenter
The point where the earthquake’s fault line seemed to have occurred.
I
IED
Improvised explosive devices, conventionally known as "bombs."
Incidence rate
The number of new cases in the population during a specified period of time.
International investment
The investment by international investors in the economic institutions and currency of a particular country. This type of investment boosts the value of that country’s currency relative to an international standard.
Intrusion
The process of emplacement of magma in pre-existing rock. Also, the term refers to igneous rock mass so formed within the surrounding rock.
Inundation
The overflowing of a particular terrain or water body by excess water. This water is generally derived from approaching storm systems or precipitation.
J
Jet Stream
A very strong, generally westerly-based winds located in a narrow and shallow stream in the upper regions of the troposphere.
K
Kalashnikov rifles
A gas-operated, automatic, assault rifle designed by Soviet engineers and predominately used throughout the world by Para-military groups. It is clip fed and has a caliber of 7.62mm.
L
Lahar
A torrential flow of water-saturated volcanic debris down the slope of a volcano in response to gravity. A type of mudflow. Usage of lahar. For a larger discussion on lahars, click here.
Lava
Magma which has reached the surface through a volcanic eruption. The term is most commonly applied to streams of liquid rock that flow from a crater or fissure. It also refers to cooled and solidified rock.
Lithosphere
The rigid crust and uppermost mantle of the earth. Thickness is on the order of 60 miles (100 km). Stronger than the underlying asthenosphere.
Low
A low is an area of low pressure. It may be found anywhere, but only has the potential to gain tropical characteristics if it is over water.
M
Magma
Molten rock beneath the surface of the earth.
Mantle
The zone of the earth below the crust and above the core.
Mass wasting
A broad range of gravity-driven rock, soil, or sediment mass movements, including weathering processes that result in gradual bluff recession, such as direct wind and rain impact.
Maximum Sustained Winds
The maximum sustained winds in the tropical system, used to determine the strength of the storm.
Mega-tsunamis
A phenomena caused by impact events resulting in massive displacements of water and tsunamis several dozen meters high.
Mercalli scale
the classification system measuring earthquake intensity that is divided into twelve levels.
Meteorological drought
This type of drought is that which is most commonly referred to in general discussion. It occurs when there is a protracted period with less than average precipitation.
Municipal
A collection of entities relating to the authority of a local or township based government.
N
Nation states
An autonomous state generally inhabited by a people sharing similar culture, language and history.
P
Per capita GNP
The Gross National Product of a particular country is the total dollar value of all goods produced within that country’s border divided by the total population of the country. As a measure of economic progress, it reflects the average income of a country's citizens and allows policy makers insight into economic strengths and weaknesses.
Persecution
The punishment of individuals based solely on factors such as race, religion, sexual orientation and socioeconomic status.
Plate
The large, subterranean rock masses that are proposed to be the bedrock for all land.
Plate Tectonics
The theory that the earth's crust is broken into about 10 fragments (plates,) which move in relation to one another, shifting continents, forming new ocean crust, and stimulating volcanic eruptions.
Positive feedback loop
A cause-and-effect chain that begins with a change to a stock and ends up amplifying the original change and pushing the system further from equilibrium.
Pyroclastic flow
A high-density mass of gases, hot ash, and larger material that flows rapidly down the sides of the volcano. Flows tend to be confined to valleys. Because of the speed at which they travel and the intense heat, pyroclastic flows and surges are one of the most dangerous hazards posed by volcanoes.
Q
Quarantine
The enforced isolation of a particular person or group of people to prevent a disease or viral infection from spreading to others.
R
Richter scale
The classification system measuring earthquake damage potential that categorizes earthquakes into ranges from 0 to 10 based on seismic activity.
Ring of Fire
The regions of mountain-building earthquakes and volcanoes, which surround the Pacific Ocean.
Rock falls
Free-fall of rock blocks from a cliff or rock outcrop
S
Saffir-Simpson Hurricane Scale
A scale classifying hurricanes by the intensity of their sustained winds, developed in 1969 by civil engineer Herbert Saffir and National Hurricane Center director Bob Simpson. Classifications are used to gauge the likely damage and flooding a hurricane will cause upon landfall. The Saffir-Simpson Hurricane Scale is used only to describe hurricanes forming in the Atlantic and northeast Pacific Oceans. Other areas use their own classification schemes.
Salinity
A relatively measurable percentage of salt content in water. Generally oceans have a greater salt content than freshwater lakes and seas.
SARS
Severe Acute Respiratory Syndrome (SARS) is an atypical form of pneumonia. It first appeared in November 2002 in Guangdong Province, China. SARS is now known to be caused by the SARS coronavirus (SARS-CoV), a novel coronavirus. SARS has a mortality rate of around 10%.
Sea level
The level of ocean waters. Municipalities are identified by their elevation above or below sea level. New Orleans, USA, for example, is 10 feet below sea level.
Security Council
The most powerful organ of the United Nations (UN). It is charged with maintaining peace and security between nations. While other organs of the United Nations only make recommendations to member governments, the Security Council has the power to make decisions, which member governments must carry out under the United Nations Charter.
Seed
The nutritive food sowed in soil and fed to cattle and other animals for greater growth and development.
Shield Volcano
A gently sloping volcano in the shape of a flattened dome and built almost exclusively of lava flows.
Slurry
Flowing river of mud.
Stratosphere
The layer of the atmosphere above the troposphere and below the mesosphere (between 10 km and 50 km), generally characterized by an increase in temperature with height.
Strike point
The geographic location at which a bomb strikes the earth’s surface. This location though, can be mounted on a building or related structure.
Storm Surge
A rise in sea that occurs before the storm nears the coast or makes landfall. Stronger storms produce stronger storm surge.
Stratovolcano
A volcano composed of both lava flows and pyroclastic material.
Sub-critical
Possessing a mass of fissionable material less than that which is needed to initiate a chain reaction. Unless the mass of the material meets the critical, or threshold value, the reaction cannot commence.
Subduction earthquakes
Earthquakes resulting from denser oceanic plates slipping under continental plates, often resulting in magnitude 8+ earthquakes
Subduction Zone
The zone of convergence of two tectonic plates, one of which usually overrides the other.
Subtropical
A storm that lacks tropical characteristics such as a warm core. Subtropical take names from the same list as tropical storms since 2002.
Super-cell thunderstorm
An extensive storm pattern characterized by high speed, rotational wind currents that spawn tornados.
Super-critical
Possessing a mass of fissionable material sufficient enough to create a rapidly progressing chain reaction.
T
Theory of plate tectonics
Alfred Wegener’s theory that these plates are in constant motion and at one point where connected to form a super-continent, Pangaea.
Thermal radiation
The energy radiated and emitted by hot surfaces through electro-magnetic waves.
Touching down
When the funnel cloud follows the intensity of the vortex towards the ground level is the stage known and indicates the complete formation of a tornado.
Toxins
A poisonous substance that is produced by by organisms that is capable of inducing disease and viral effects in addition to mitigating the effects of antibodies.
Tropical Cyclone
The general name for a storm that has a warm core, a closed eye, and winds greater than 73 mph. Synonymous with the words Hurricane, Cyclone and Typhoon.
Tropical Depression
A system with tropical characteristics with winds less than 39 mph.
Tropical Disturbance
An area of convection originating in the tropics. Has the potential to develop into a tropical depression.
Tropical Storm
A storm with tropical characteristics that has not reached hurricane strength with winds between 39 and 73 mph.
Tropical Wave
A system of convection, stronger waves may become more organized and develop into Tropical Depressions.
U
Unilateral
Actions undertaken by a sole country or organization, without any external involvements.
United Nations (UN)
An international organization that describes itself as a "global association of governments facilitating cooperation in international law, international security, economic development, and social equity." It was founded in 1945 by 51 states, replacing The League of Nations. As of 2005 it consists of 191 member states.
Updrafts
The wind that is pulled upwards by the rotational wind currents
USA PATRIOT Act
The Uniting and Strengthening America by Providing Appropriate Tools Required to Intercept and Obstruct Terrorism Act of 2001 is an act of federal legislation in the United States that dramatically expands the authority of U.S. law enforcement for the stated purpose of fighting terrorist acts in the United States and abroad. It is also used to detect and prosecute other alleged potential crimes such as providing false information on terrorism. It was renewed in March 2006 with certain provisions left out.
Utilitarian
The economic theory advocated by Jeremy Bentham stating that all actions should be directed towards creating the greatest benefit for the great number of people.
V
Vent
The opening at the earth's surface through which volcanic materials issue forth. Usage of vent.
Viscosity
A measure of resistance to flow in a liquid (water has low viscosity while honey has a higher viscosity.)
Volcano
A vent in the surface of the Earth through which magma and associated gases and ash erupt; also, the form or structure (usually conical) that is produced by the ejected material.
Volcanic Cone
A mound of loose material that was ejected ballistically.
Vector
Carrier of an infectious agent; capable of transmitting infection from one host to another; especially the animal that transfers an infectious agent from one host to another, usually an arthropod.
W
Wavelength
The distance between successive points of equal amplitude and phase on a wave (for example, crest to crest or trough to trough).
Weapons of Mass Destruction
Any weapon or device that is intended, or has the capability, to cause death or serious bodily injury to a significant number of people.
Wind Shear
change in wind speed or direction over height
World Health Organization
A specialized agency of the United Nations, acting as a coordinating authority on international public health, headquartered in Geneva, Switzerland. WHO was established by the UN on April 7, 1948. The current Director General is Lee Jong-Woo.