Mont Saint Helens : Diferéncia entre versions

Pendent l'ivèrn de 1980–1981, un [[glacièr]] nòu apareguèt. Uèi oficialament nomenat [[Crater Glacier]], èra ancianament conegut jol nom de Tulutson Glacier. Ombratjat per las parets del cratèr e alimentat per las importantas casudas de nèu e avalancas, creissèt rapidament (4.3 m per an). En 2004, cobrissiá aperaquí 93 km2, e èra devesit per lo dòma central en dos lòbes. Generalament a la fin de l'estiu, lo glacièr es fosc amor de las casudas de ròcas del cratèr e de cendres de las erupcions. En 2006, lo [[glaç]] aviá una espessor mejana de 100 m. amb un maximun de 200 m., gaireben tant espés que lo pus ancian e pus gròs glacièr del Mont Rainier, lo [[Carbon Glacier]]. Tot lo glaç es posterior a l'erupcion de 1980, çò que ne fa un glacièr fòrça jove geologicament. Pasmens, lo volum del glacièr nòu es aperaquí identic al de totes los glacièrs d'abans 1980 combinats.<ref name="Brugman81">{{Ligam web | last = Brugman | first = Melinda M. | coauthors = [[Austin Post]] | títol = USGS Circular 850-D: Effects of Volcanism on the Glaciers of Mount St. Helens | url= http://pubs.er.usgs.gov/publication/cir850D | year = 1981 | accessdate = 2007-03-07 }}</ref><ref>
{{Ligam web | last = Schilling | first = Steve P. | coauthors = David W. Ramsey, James A. Messerich, and Ren A. Thompson | títol = USGS Scientific Investigations Map 2928: Rebuilding Mount St. Helens | url= http://pubs.usgs.gov/sim/2006/2928/ | date = 2006-08-08 | accessdate = 2007-03-07 }}</ref>
 
Amb la recenta activitat volcanica que comencèt en 2004, los lòbes del glacièr son butats suls costats e cap amont per la creissença del dòma volcanic novèl. The surface of the glacier, once mostly without crevasses, turned into a chaotic jumble of [[icefall]]s heavily criss-crossed with [[crevasse]]s and [[serac]]s caused by movement of the crater floor.<ref name="VR">{{cite web|title=Volcano Review|archiveurl=http://replay.web.archive.org/20080626134702/http://www.fs.fed.us/gpnf/mshnvm/volcano-review/documents/Volcano_Review_2008_Final_lowrez-201.pdf|archivedate=2008-06-26|format=PDF|publisher=[[US Forest Service]]}}</ref> The new domes have almost separated the Crater Glacier into an eastern and western lobe. Despite the volcanic activity, the termini of the glacier have still advanced, with a slight advance on the western lobe and a more considerable advance on the more shaded eastern lobe. Due to the advance, two lobes of the glacier joined together in late May 2008 and thus the glacier completely surrounds the lava domes.<ref name="VR"/><ref name="SE">{{cite web|title=MSH08_aerial_new_dome_from_north_05-30-08|url=http://vulcan.wr.usgs.gov/Imgs/Jpg/MSH/MSH08/MSH08_aerial_new_dome_from_north_05-30-08_med.jpg|publisher=[[United States Geological Survey]]|first=Steve|last=Schilling|date=2008-05-30|accessdate=2008-06-07}} - Glacier is still connected south of the lava dome.</ref><ref name="NT">{{cite web|title=MSH08_aerial_st_helens_crater_from_north_05-30-08|url=http://vulcan.wr.usgs.gov/Imgs/Jpg/MSH/MSH08/MSH08_crater_glacier_arms_touching_05-30-08_med.jpg|publisher=[[United States Geological Survey]]|first=Steve|last=Schilling|date=2008-05-30|accessdate=2008-06-07}} - Glacier arms touch on North end of glacier.</ref> In addition, since 2004, new glaciers have formed on the crater wall above Crater Glacier feeding rock and ice onto its surface below; there are two rock glaciers to the north of the eastern lobe of Crater Glacier.<ref>{{cite journal | author = Haugerud, R. A. | coauthors = Harding, D. J., Mark, L. E.; Zeigler, J., Queija, V., Johnson, S. Y. | title = Lidar measurement of topographic change during the 2004 eruption of Mount St. Helens, WA | date = 2004-12 | bibcode= 2004AGUFM.V53D..01H | last2 = Harding | last3 = Mark | last4 = Zeigler | last5 = Queija | last6 = Johnson | volume = 53 | pages = 01 | journal = American Geophysical Union }}</ref>
 
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