Word: magma
(lookup in dictionary)
(lookup stats)
Dates: all
Sort By: most recent first
(reverse)
...another Northwestern peak--Mount St. Helens--went bad the same way, leading to a volcanic explosion that blew out the north face of the mountain, killing 60 people. While the more stable magma in Mount Rainier makes an eruption unlikely, the corroded state of the mountain could make a landslide even more devastating. Mount St. Helens, after all, had been baking for 100 years after its last blast; Mount Rainier has cooked for 500. "It's only a matter of time," says Dan Miller, a volcanologist with the U.S. Geological Survey (USGS), "before those towns near Rainier are buried...
...their fearsomeness volcanic mountains are relatively simple geologic structures--little more than lesions in the earthly dermis that suggest a fever condition far below. Volcanologically active areas generally lie atop clashing tectonic plates, where fractures five or six miles belowground create chambers into which magma rises and pools. The faster the plates collide, the more volcanic chambers are formed, which is why so many eruptions take place in the geologically active area of the Pacific known as the Ring of Fire...
...Magma held in the chamber eventually makes its way toward the surface through channels in the overlying rock. As the ascending ooze climbs higher, the pressure on it is dramatically reduced, allowing gases trapped within to bubble out like carbonation in an opened bottle of soda. As this happens, the magma takes on a foamier consistency, increasing its speed and mobility. When this scalding froth rises high enough to make contact with subterranean water, the water flashes into steam, turning the whole hellish mix into a natural pressure cooker. Finally, the explosively pressurized magma blasts out of the earth...
...using the orbital high ground to study the volcanic underground. In Alaska, USGS researchers have placed satellite receivers at different points on the sloping side of the Augustine volcano and tuned them also to the gps. Like any volcanic mountain, Augustine is swelling slightly as it fills with magma. The degree of this deformation--as calculated by the gps--can help determine the imminence of the eruption. Elsewhere, scientists are leasing time on European or Japanese satellites to take photos of volcanic peaks as they undergo a seismic event like an earthquake. Imaging hardware then measures the precise distance between...
...magma rises in a volcano, light molecules like carbon dioxide bleed off more than heavier gases like sulfur dioxide. The higher the CO[2] levels, the likelier an eruption. If magma gets stuck in the gullet of the mountain, SO[2] predominates. The more SO[2], the more stagnant the magma and the less probable an eruption. The problem is that taking accurate measurements may require climbing almost directly into a volcano--a decidedly dangerous proposition...