Tham khảo tài liệu 'earth sciences - notable research and discoveries part 10', khoa học tự nhiên, địa lý phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | GLOSSARY aquifer underground area that has enough water to supply a well asthenosphere a weak layer of rock in the upper mantle caldera a basin or sink formed by the collapse of a volcano chron See magnetic chron compression waves propagating disturbances in which material alternately squeezes compresses and pulls apart convection mechanism of heat transfer by which flows of material such as liquid or molten rock carry heat from warm to cool regions crust thin layer covering Earth s surface extending from continents to an average depth of about 22 miles 35 km and from the ocean floor to an average depth of about four miles km current in electricity a flow of electric charges desalination removal of salt and minerals from seawater in order to render it drinkable dormant describes a volcano that has been inactive for a considerable period of time electrons negatively charged particles normally found in motion around an atom s nucleus epicenter in seismology the ground directly above an earthquake s focus 196 Glossary 197 fault break or crack in rocks where one side has moved relative to another focus in seismology the site of an earthquake s origin or initial disturbance which is usually located under the surface and propagates from this point in all directions fossil fuels energy resources oil coal and natural gas formed long ago from the remains of organisms hydrology the study of the properties distribution and circulation of water inner core Earth s solid center composed of iron with a little nickel with a radius of about 756 miles 1 220 km ions charged particles isotopes atoms of the same element but with different numbers of neutrons lava molten rock that erupts from a volcano lithosphere crust and uppermost mantle to a depth of about 60 miles 100 km Mw moment magnitude scale sometimes abbreviated as M magma molten rock beneath Earth s surface magnet an object having the capacity to exert an attractive force on iron in its vicinity magnetic chron period in
