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Volcanoes and Earth Processes. Volcanoes. Active : a volcano that is currently erupting, or has erupted very recently. Extinct : a volcano that has erupted in the past, but that likely will not erupt in the future.
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Volcanoes Active: a volcano that is currently erupting, or has erupted very recently. Extinct: a volcano that has erupted in the past, but that likely will not erupt in the future. Dormant: a volcano that is not erupting, but could realistically erupt in the future.
Active, Dormant, Extinct • These terms do not help us very much because the “recharge” of an active volcano occurs over ‘geological time scales’ (long periods of time), and therefore makes the definition problematic. • Some organizations that research volcanoes have suggested that if a volcano has erupted in the past 12 000 years (during the Holocene epoch), it is to be considered active.
Dante’s Peak Terminology: Volcanologist: a researcher who studies volcanoes. Seismic Activity: vibrations and movement within the crust (can cause earthquakes and volcanic activity) Seismograph: a device that measures seismic activity Tiltmeter: a device that measures the change in shape (uplift/bulge) as pressure builds within a volcano. Pyroclastic Flow: a wave of very hot rock fragments, gases and ash that have been ejected from an active volcano. (pryo means fire, clastic refers to fragments). They can reach temperatures of 1000 degrees celcius and move at up to 700 km/h. Magma: molten rock material inside the earth. Lava: molten rock material on the earth’s surface.
Earth Processes • Land is built by tectonic force and volcanoes (new igneous rock). This is often known as ‘mountain building.’ • Land is worn-down by erosion: the movement of sediment (small broken pieces of rock) to low-lying areas (usually seas/oceans) • Eroded sediments will become sedimentary rock.