Volcanoes and volcanism are not restricted to the planet Earth. Manned and unmanned planetary explorations, beginning in the late 1960's, have furnished graphic evidence of past volcanism and its products on the Moon, Mars, Venus and other planetary bodies. Many pounds of volcanic rocks were collected by astronauts during the various Apollo lunar landing missions. Only a small fraction of these samples have been subjected to exhaustive study by scientists. The bulk of the material is stored under controlled-environment conditions at NASA's Lunar Receiving Laboratory in Houston, Tex., for future study by scientists.
Mariner 9 imagery of Olympus Mons volcano on Mars compared to the eight principal Hawaiian islands at the same scale. Mariner 9 mosaic imagery provided by NASA/JPL.
From the 1976-1979 Viking mission, scientists have been able to study the volcanoes on Mars, and their studies are very revealing when compared with those of volcanoes on Earth. For example, Martian and Hawaiian volcanoes closely resemble each other in form. Both are shield volcanoes, have gently sloping flanks, large multiple collapse pits at their centers, and appear to be built of fluid lavas that have left numerous flow features on their flanks. The most obvious difference between the two is size. The Martian shields are enormous. They can grow to over 17 miles in height and more than 350 miles across, in contrast to a maximum height of about 6 miles and width of 74 miles for the Hawaiian shields.
Voyager-2 spacecraft images taken of Io, a moon of Jupiter, captured volcanoes in the actual process of eruption. The volcanic plumes shown on the image rise some 60 to 100 miles above the surface of the moon. Thus, active volcanism is taking place, at present, on at least one planetary body in addition to our Earth.
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Tonight: Clear. Low around 35, with temperatures rising to around 37 overnight. Northwest wind around 5 mph.
Tuesday: Sunny. High near 62, with temperatures falling to around 60 in the afternoon. North northwest wind 3 to 20 mph, with gusts as high as 30 mph.
Tuesday Night: Mostly clear. Low around 34, with temperatures rising to around 36 overnight. North wind 6 to 20 mph, with gusts as high as 30 mph.
Extended ForecastReporting Station: Mount Shasta
Updated: Mon, Apr 12 at 8:17 PM
Weed lies along the boundary between two of California's northernmost geologic provinces: the Klamath Mountains and the High Cascades. Although underlain by different rock types (ancient crystalline rocks in the Klamath and young volcanic rocks in the Cascades) both provinces were formed by the same process: subduction.
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