Glossary
The glossary below consists of terms used in the standard background pages and easy background pages.
active fault
A fault that is likely to have another earthquake sometime in the future. Faults are commonly considered to be active if they have moved in the last 10,000 years.
atomic clock
Very accurate clock which uses the known properties of certain atoms to record time.
cadastral maps
Maps which show who owns land.
cartography
The process of drawing or making maps.
coordinates
Angular or linear values that give the position of a point on a map.
chlorine
A chemical element that can be added to city drinking water supplies to kill harmful bacteria.
contamination
Where something unwanted or harmful enters something useful e.g. sewage contaminating the drinking water.
covenants
Legal agreements to do with land use.
datum
A set of values used to define a specific geodetic system e.g. MSL - Mean Sea Level.
The weight of a known volume of material.
easements
The legal right to do something on your own or someone else's land.
echo-sounding
The modern technique used to measure water depth by bouncing sound waves off the sea floor.
elevation
The height above mean sea level.
epicentre
The point on the Earth's surface vertically above the hypocentre.
Process of wearing away and transporting of rocks by wind, rain or ice.
A break in rock across which there is observable movement.
fissure
A long narrow crack in the ground caused by earthquakes.
geocaching
A sport where people use GPS to hide and seek containers called caches or geocaches anywhere in the world.
geographic datum
A datum which is based on the Earth's centre of mass. The advantage of the geocentric datum is its direct compatibility with satellite-based navigation systems such as GPS.
A scientist trained in the study of the Earth.
The science of the make-up, shape and history of the Earth.
geospatial
To do with location.
geospatial data
Data or information about the location of specific things.
GPS
Global Positioning System - uses the known distance between satellites to calculate exact locations.
GIS
Geographic Information Systems - maps that combine sets of information.
Green Zone
Housing areas in Canterbury where houses are able to be rebuilt.
hydrographic surveys
A survey which records the physical features of waterways.
hydrography
The science of measuring and describing the physical features of waterways.
hypocentre
The point on the fault plane where the rupture starts.
infrastructure
Services such as roads and water systems.
intersection
Sometimes called triangulation. Where the known angles and distance between points is used to calculate the location of a distant point.
intensity
A measure of how strongly an earthquake manifests at the surface, based on its observable effects on people, buildings and the environment. Intensity is usually ranked using the 12 point Modified Mercalli Intensity (MMI) scale.
lateral shear
Sideways separation or break caused by land movement.
lateral spread
Where land slips downhill due to liquefaction below the surface.
latitude
Distance from the equator in degrees, shown as horizontal lines on a map.
liquefaction
A process in which water-saturated sediment temporarily loses its strength and acts as a fluid.
longitude
Distance east or west from Greenwich, England, in degrees shown as vertical lines on a map.
magnitude
A measure of the energy released by an earthquake at its source. Magnitude is commonly determined from the shaking recorded on a seismograph. Each unit of magnitude on the scale represents a substantial increase in energy. For example a magnitude 5 releases 30 times more energy than a magnitude 4.
nautical charts
Charts or maps of features at sea such as reefs, coastlines, shipping hazards and sometimes water depths and currents.
Red Zone
Housing areas in Canterbury where land damage was so severe from the quakes that houses will not be rebuilt in the near furture.
Resource Consent Applications
Used to apply for the legal right to use a resource.
Rūaumoko (or Rūamoko)
According to Māori tradition earthquakes are caused by Rūaumoko - the god of earthquakes and volcanoes.
rū whenua
The Māori word for earthquakes, which translated means the shaking of the land.
sandblows
When waves from a large earthquake pass though wet, loose sand, patches of sand erupt from below the surface onto the ground and form sandblow deposits. Also nicknamed miniature sand volcanoes.
satellites
Objects which are sent into space to orbit the Earth and send and receive information.
SCIRT
Stronger Christchurch Infrastructure Rebuild Team - an alliance of construction companies working together to rebuild Christchurch's services such as roads and water systems.
slumping
When loosely consolidated materials or rock layers move a short distance down a slope.
sounding line
A line with a lead weight on the end which is lowered into water to measure the water depth.
A particular layer of a rock.
storm water
Rain water that has drained off buildings, solid surfaces and roads.
surveyors
People who specialise in making accurate measurements on the surface of the earth to make maps.
theodolite
An optical instrument used by surveyors to measure angles to give exact locations of distant points.
topographic
The shape of the Earth's surface.
topographic map
Shows the shape of the surface, including altitude as well as natural and physical features - sometimes called a contour map.
trigonometry
A type of maths that measures the angles and sides of triangles and uses this information and set formula to find the unknown sides and angles. This type of maths can also be used to find the location of distant points.
utilities
Services such as water pipes and power lines.
wastewater
Used water that needs treatment such as sewage and grey water.
waymarking
An activity where people can locate and log interesting locations anywhere in the world.
