archaeology The scientific study of the physical remains of ancient human cultures and the art of interpreting their significance.
Bronze Age Period of human cultural development in Europe and the Near East characterized by the use of bronze tools and weapons that began between 4000 and 3000 years ago and ended with the Iron Age (about 1200 B.C.).
etiology From a Greek term meaning cause, origin, or source; in the study of ancient myth, it refers to oral traditions that attempt to explain the origins of natural or social phenomena.
geomythology The study of ancient oral traditions that preserve memories of prehistoric geologic events, such as earthquakes or volcanic eruptions.
lahar An Indonesian term for a debris flow or mudflow originating on a volcano.
Minoan culture An ancient civilization centered on Crete and characterized by the building of large palace complexes, such as that at Knossos; it dominated the Aegean region from about 2000 to 1450 B.C.
mudflow A water-saturated mass of rock debris that moves downslope as a liquid under the pull of gravity; it can travel many tens of miles beyond its source.
Neolithic The New Stone Age; in Europe and the Mediterranean basin, it refers to prehistoric cultures using stone implements and characterized by settled agrarian pursuits.
phreatic Refers to a steam eruption that produces no fresh magma. A common precursor of eruptive activity, it is caused when groundwater, heated by a magmatic source, flashes into steam.
Plinian eruption Named for Pliny the Younger, a violently explosive eruption that ejects a large volume of tephra high into the stratosphere.
pyroclastic A Greek term meaning fire-broken; it refers to fragmental rock ejected during an eruption.
pyroclastic flow A dense, hot, dry mixture of gas and incandescent rock fragments that travels rapidly along the ground surface, typically at speeds of hundreds of feet per second.
pyroclastic surge A turbulent cloud of gas and fine rock particles that flows over and above the ground surface at extremely high velocities. More dilute than pyroclastic flows, surges are not topographically constrained but sweep over ridges, hills, and other topographic obstacles.
tephra Rock fragments blown into the air above an erupting volcano; tephra ranges in size from fine ash to blocks many tens of feet in diameter.
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