Great officer of the Legion d'Honneur, the chemist Alfred Lacroix, professor at the Museum of natural history since the first of april , carried on the function of perpetual secretary of the Academy of Sciences during 34 years.
Abstract His grandfather and his father were chemists in Macon. The eruptions were overshadowed by the preceding eruptions in , which destroyed the city of St.
Pierre and its 26, inhabitants. The death and destruction was caused by a phenomenon that was new to the then young science of volcanology: the nu?
Nuee ardente - a French term meaning glowing cloud - refers to a high-speed, high-temperature mixture of hot volcanic gas and rock fragments that behaves like a fluid. These mixtures are typically associated with dome-building eruptions, like the one that is currently underway at Mount St. Today, most volcanologists prefer the term "pyroclastic flow" to nu? The eruption sequence was more conducive to study than its predecessor, because it lasted longer and because it was less explosive than the eruptions.
A lava dome was slowly growing at the summit of Mt. Intermittently, parts of the dome would collapse and generate pyroclastic flows that traveled down a valley that headed on the volcano.
In an act that is today considered lunacy, Perret constructed a small wooden observation cabin atop a low hill in a valley. From this observation post, he watched the pyroclastic flows form and travel past him, on one or both sides of his perch. Usually the flows were rather small and were confined to the valley bottom.
But one day he got more than he bargained for. In his own words? It was unstably poised and its fall seemed imminent. Just at the close of the swiftly passing tropical twilight, in the dead calm between day and night winds, an unusual sound brought me to the cabin door. The whole mass had fallen, leaving a great scar on the dome from which poured forth an ash-cloud of inky blackness, expanding upward as it rushed down the talus slope like a nuee ardente.
Joe Chandler is a marketing consultant with experience in education, customer service, and business and consumer electronics. Chandler has been writing for a year. He has over 20 years in corporate America and education, with an M. He is a Navy veteran trained in nuclear power plant operation.
Stages of a Volcano Eruption. What Were the Effects of the Tambora Eruption? Facts About Mount Etna. Facts on Volcanology. Mauna Loa Facts for Kids. Negative Effects of Shield Volcanoes. His strong interest in volcanism began with his first geologic project studying Precambrian volcanic rocks in the Upper Peninsula of Michigan. This interest in volcanic phenomena intensified with subsequent work in the San Juan volcanic field of southwestern Colorado and on Augustine Volcano in lower Cook Inlet, Alaska.
The Augustine study was the basis for his doctoral dissertation, completed in at the University of Washington, Seattle. Following completion of his Ph. His work on volcanic gases brought him to the U. Geological Survey in , where he was assigned to expand the program for monitoring volcanic emissions in Alaska and the Cascade Range. A specific objective of such monitoring is to test whether or not changes in gas geochemistry might provide precursory clues of impending eruptive activity.
Thus, it was natural that, when Mount St. Helens reawakened in March , Dave Johnston was one of the first geologists on the volcano.
Image taken from hovering helicopter.
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