E Flashcards
Earthquake intensity
A measure of how much damage an earthquake causes. Several scales are in use which have developed over time from the very crudest, subjective observations of the 19th century, to relatively sophisticated, empirical forms today. ie: Rossi-Forel Scale; Omori Scale; Mercalli Scale; MCS Scale; MMI Scale; MM56; MSK64 Scale; EMS-98 Intensity Scale; JMA Seismic Intensity Scale.
Earthquake
Sudden release of energy through the earth’s crust in the form of seismic waves. Tension builds up within the crust as convectional forces in the mantle try to move the plates above but are prevented from doing so by friction between plates. When friction is overcome, an earthquake occurs.
Earthquake magnitude
A mathematical measure of the strength of an earthquake based on the maximum amplitude of the seismic waves produced. See Richter Scale.
Earth tremor
Technically any earthquake can be said to consist of earth tremors, as the word tremor simply means shaking. However, it is generally accepted that the phrase earth tremor should relate only to smaller earthquakes, i.e. those of low magnitude and intensity. These would ordinarily cause little or no damage but may have a greater impact if they come in the immediate aftermath of a high magnitude and intensity earthquake which has already weakened and destabilized many structures. Where the line should be drawn is not agreed.
Easting
The vertical gridlines on a map so called because their numeric value increases from west to east.
Ebb tide
A falling tide.
EC
See European Community.
Ecology
Study of the ecosystem with particular reference to the relationships between plants and animals and the environment.
Economic activity
Work or industry undertaken for economic purposes.
Four sectors:
Primary - exploitation of raw materials.
Secondary - processing and production.
Tertiary - service provision.
Quaternary - high-technology industry such as research, or IT.
Economic growth
The growth of gross national product over time. Calculation is highly complex and does not necessarily relate to improvements in the economic experience of the general population as great disparities of wealth can occur with the bulk of the wealth becoming concentrated in the hands of a small elite.
Economic man
Assumption used in many models of economic geography that human decision-making and subsequent behaviour is based on rational economic motives. A weakness in these models as modern studies have shown great variation in motive as well as ability to make decisions and access to information. Poor ability and information will lead to poor decision-making even if following an economic motive.
Economic rent
Also known as locational rent, the profit to be derived from land. Proposed by von Thunen, it is calculated by subtracting the costs of production and transport of a unit of produce from the market price for that unit and multiplying by the total yield for the area of land in question.
Economically less developed country (ELDC)
Previously known as undeveloped, Third World, The South, less developed and less economically developed country (LEDC). A country whose development has yet to lead to the presence of welfare criteria that allow the country to be termed economically more developed. Terminology has changed to try and avoid unwarranted perceptions that people in different places may in some way be better than, or superior to, people in other places.
Economically more developed country (EMDC)
Previously known as developed, First World, The North, more developed and more economically developed country (MEDC). A country whose development has led to the presence of welfare criteria that allow the country to be termed economically more developed. These are generally the wealthiest countries in the world although anomalies occur. Some oil-rich Middle Eastern countries are very wealthy but do not display social welfare criteria. Some former Second World countries struggle economically but display complex, modern political structures. Terminology has changed to try and avoid unwarranted perceptions that people in different places may in some way be better than, or superior to, people in other places.
Economies of scale
Lower per unit costs achieved by large-scale output.
Two kinds:
1. Internal - benefit the firm: specialized labour is more efficient, fixed costs spread over more units of production, purchasing is cheaper with bulk buying, larger firms can enjoy lower cost of borrowing.
2. External - benefit the industry: specialized labour pool, attract pool of suppliers.
Ecosystem
A system existing in a particular region, at a variety of scales, where organisms exist in communities and interact with the abiotic environment around them.
Ecotone
The transition zone between very diverse ecosystems e.g. from tropical rainforest to savanna.
Ecotourism
Maintenance of very small-scale, low density tourist developments, usually in locations where the environment is particularly fragile or sensitive to human activity, so that degradation does not occur in those areas.
Edaphic
Literally of the soil. Any soil properties which affect plant growth and distribution.
EEC
See European Economic Community.
Effective precipitation
Precipitation available for actual use by plants.
Effluent
Water released to the environment after treatment.
EFTA
See European Free Trade Association.
ELDC
See economically less developed country.
ELDW
Economically less developed world - collectively all the economically less developed countries (ELDCs).
Elevation
Height above sea-level.
el Nino
A periodic reversal in the usual pressure, wind and precipitation patterns of the tropical Pacific region which can have severe implications for human activity. Excellent background and explanations here: http://www7.nationalacademies.org/opus/elnino.html
ELR
See environmental lapse rate.
Eluviation
Removal of material from a soil horizon, usually downward.
Embargo
An order to prohibit trade with a particular country.
EMDC
See economically more developed country.
EMDW
Economically more developed world -collectively all the economically more developed countries (EMDCs).
Emergent coast
A coast that has experienced net sea level fall and the characteristics particular to it as a result.
Emergent plants
See aquatic plants.
Emigration
Movement of people away from an area, region or country.
Employment sector
The broad types of economic activity within which jobs are provided: primary, secondary, tertiary and quaternary.
Employment structure
The percentage of people employed in each of the four major employment sectors.