When you click on words in the glossary, you will access the text that is relevant to it.
aa lava - lava that has a rough surface when cooled
active volcano - a volcano that might erupt at any time
ash (or tephra) - tiny rock fragments that are ejected from a volcano during an eruption
asthenosphere - the uppermost ╥plastic╙ part of the earth╒s mantle, about 600 km thick (the layer below the lithosphere that is marked by low seismic wave velocities and high seismic wave attenuation)
basalt - an igneous rock formed when runny lava cools and hardens
caldera - a large crater (usually at least 5 km in diameter) formed when a volcano explodes
continent - One of the seven main land masses on earth: Asia, Africa, Europe, North America, South America, Australia and Antarctica
convection - in seismology, a form of motion in the mantle which occurs when hot matter rises and colder matter sinks
core - the hard centre of the earth, consisting of solid iron surrounded by liquid iron and nickel
crater - the funnel-shaped opening at the summit of a volcano, usually 1 km or less in diameter
crater lake - a lake which forms in a crater when the lava has cooled
crust - the outer ╥skin╙ of the earth
dormant volcano - a volcano that is not active but is expected to erupt again
epicentre - the point on the earth╒s surface which is immediately above the focus (the point at which the rock broke) of an earthquake
extinct - a volcano that is not expected to erupt again
fault - a break in the earth╒s crust which may range from centimetres to kilometres in length
foreshock - a tremor that occurs prior to an earthquake
geothermal energy - energy produced by harnessing the water or steam from hot rocks
geyser - a hot spring that erupts hot or boiling water and steam
hotspot volcano - a volcano that occurs in the middle of a plate above a hotspot of magma
hot spring - a pool or spring that is formed when seeping water that has been warmed by magma or heated rocks is returned to the surface
island arc - a chain of volcanic islands formed when magma rises from a subduction zone (e.g. Japan)
lahar - another name for a mudflow
lava - magma or molten rock that has erupted onto the surface of the earth
lithosphere - the earth╒s crust
lithospheric plate - a section of the earth╒s crust that ╥floats╙ on the mantle
L waves or Love waves - the third and most destructive energy waves to be released in an earthquake
magma - molten rock in the mantle that forms igneous rocks when cooling
magma chamber - a pocket of magma in the earth╒s crust
mantle - the main bulk of the earth between the core and the crust
Mercalli Scale - the scale which measures the intensity of an earthquake dependent on observation of damage caused
mid-ocean ridge - an oceanic mountain range occurring where plates are moving apart
mudflow - a fast-moving mixture of ash and water during or following a volcanic eruption (sometimes called a lahar)
mud pot - a hot spring in which water has mixed with mud
outer core - the liquid iron and nickel that surround the earth╒s solid core
pahoehoe lava - a type of lava that cools to give a twisted, rope-like appearance
pillow lava - lava which erupts underwater and cools into characteristic pillow shapes
primary waves (or P waves) - the first energy waves released in an earthquake
pumice - a volcanic rock formed by cooled frothy lava which contains so much air that it can float in water
pyroclastic flow - a fast-flowing cloud of hot gases and ash which is blown from the mouth of a volcano
Richter Scale - a scale of measurement of seismic intensity in an earthquake
Ring of Fire - an area of volcanic activity which rings the Pacific Ocean
secondary waves (or S waves) - the second set of energy waves released in an earthquake
seismic activity - any of the effects caused by an earthquake
seismology - the study of seismic activity and earthquakes
spreading ridge - a ridge formed when magma rises to fill the rift when two plates move apart
subduction - the process of one plate sinking beneath the other into the earth and pulling the ocean lithosphere
surface waves - the third and most destructive energy waves to be released in an earthquake (there are 2 types - Love waves and Rayleigh waves)
tephra - volcanic ash
volcano - you should know what this means by now! A volcano is an opening in the surface of the earth from which molten rock, called magma, and gases escape