Word: magma
(lookup in dictionary)
(lookup stats)
Dates: during 1990-1999
Sort By: most recent first
(reverse)
...other towns in this part of the Pacific Northwest--including Microsoft's hometown, Redmond--Orting was built in the shadow of Mount Rainier, and Mount Rainier has a nasty little secret. Beneath the 14,410-ft. mountain's sugary caps and forested flanks lies a mammoth, smoldering pot of magma. Summoned up from the earth's subterranean ovens perhaps 40 miles below, the molten rock simmers under the mountain at up to 3600[degrees]F. As the magma cooks the rocky innards of Mount Rainier, it slowly helps turn them into unstable clay. At the same time this internal furnace...
...dozen different ways. An atmospheric mist of sulfur dioxide, for example, could have stoked lethal storms of acid rain. Carbon dioxide, injected into the atmosphere by erupting volcanoes, could have trapped solar heat, disrupting climate through global warming. Even the physical force exerted by the rising plume of molten magma could have contributed to the extinction by uplifting a substantial section of the earth's crust. Since temperatures fall with elevation, says Renne, snow and ice would have quickly accumulated, wrecking ecosystems at higher elevations and contributing to the drop in sea level...
...tracking of seismic waves generated by earthquakes and explsions, which indicates that such waves emanating from a huge impact would be focused by the earth, converging on the antipode and releasing their energy there. This concentration of energy might heat and distort the crust, eventually creating plumes through which magma could burst to the surface...
...another mechanism capable of inducing fracture has been suggested by the Landers earthquake. Because the quake triggered scores of sympathetic vibrations in volcanic and geothermal regions, some scientists have speculated that the Landers event shook underground magma chambers as though they were big cans of soda. The gas that fizzed forth could, in turn, have forced open a gap that eased the slip of surrounding rock. Whatever the mechanism, experts agree, it has only hastened the fracture of a fault zone that was already stressed up and ready...
...Tilling's colleagues, geophysicist Bernard Chouet, believes he may have found an answer to this dilemma. Prior to many large-scale eruptions, he says, seismometers have picked up tremors that appear to be caused, not by the fracturing of rock, but by low-frequency waves that resonate through the magma itself. While their origin remains a mystery, these vibrations may result from small surges of gas and molten rock. Large numbers of such signals preceded Mount St. Helens' 1980 blast. They also appeared before the unexpected explosion of Mexico's El Chichon in 1982, the blowup of Colombia's Nevado...