... of the underlying lava formation, as well as the packing features observed in the breccia, are considered to be deceleration structures. Introduction Huge landslides of volcano flanks, whether or not initiated by magmatic intrusions, have been recognized as catastrophic events since the 1980 Mount St Helens...

.... 95 , doi: 10.1785/0220240112 . Lacroix A. 1904 . La Montagne Pelée et ses éruptions , Vol.  1 , Masson , Paris, France (in French). Lipman P. W. , and Mullineaux D. R. 1981 . The 1980 eruptions of Mount St. Helens, Washington , U.S. Geol. Surv. Rept. 1250, Profess...

... to become buoyant. Currently, the turbulent velocity fields of volcanic eruption columns are unknown, and therefore numerical models of eruption columns remain untested against geologic observations. Through extensive reevaluation of video and photographs of the 18 May 1980 eruption of Mount St. Helens...

... of compositional diversity of plagioclase crystals in magmas from the 1980 891 and 2004 2005 eruptions of Mount Saint Helens. Journal of Petrology, 63, 1-34. 892 Schmelzer, J.W.P. (2008) Crystal nucleation and growth in glass-forming melts: experiment and theory. 893 Journal of Non-Crystalline Solids, 354, 269 278...

.... During the period 2004–2008, Mount St. Helens erupted seven dacite spines. Each was extruded from a vent at the south margin of the 1980–1986 lava dome, and each brought the faulted conduit margin to the surface, which was formed in the preceding days to months ( Scott et al., 2008 ). The third, fourth...

... upstream from their final location in the PF deposits ( Buesch, 1992 ; Pollock and Brand, 2012 ). For example, PFs produced during the 18 May 1980 eruption of Mount St. Helens (Washington State, USA) entrained blocks from the shattered surface of debris avalanche deposits and transported them tens...

.... Andesitic stratovolcanoes are highly unstable features and regularly collapse catastrophically, producing extremely destructive mass flows known as debris avalanches ( Siebert, 1984 ). The best-witnessed collapse of this type was the 18 May 1980 event at Mount Saint Helens, which emplaced a 2.5 km 3 debris...

.... 1986 . Summary of pre‐1980 tephra‐fall deposits erupted from Mount St. Helens, Washington State, USA , Bull. Volcanol. 48 , no.  1 , 17 – 26 , doi: 10.1007/BF01073510 . Myers B. , and Driedger C. L. 2008 . Eruptions in the Cascade range during the past 4,000 years , US Geol...

.... Mullineaux D.R. eds., The 1980 eruptions of Mount Saint Helens : U.S. Geological Survey Professional Paper 1250, p. 461 – 478 . McPhie J. Doyle M. Allen...

... created Coldwater and Castle lakes in the Toutle Valley after the 1980 Mount Saint Helens eruption are a modern analog ( Dahm et al., 2005 ). The upper ash bed is discontinuous or not recognizable in some places, but this appears to be due to local, limited disturbance soon after deposition. The lower...

... tiltmeters at five locations at Mount St. Helens during the 2004-2008 eruption, with most data recorded at 1 Hz and telemetered out of the crater ( A nderson et alii , 2010 ) ( Fig. 9 ). Three tiltmeter sites (REM, SEP, and NDM/NDL) were located on the old 1980s lava dome, while two more sites were...

... the 2007 Ruapehu flow, 29 individual site measurements of U , g, h , and R were obtained for well-documented lahars at Nevado del Ruiz, Mount Saint Helens, and Ruapehu. Data for 25 of these sites show that U > C and that bow-wave formation must have occurred, because their generation was faster...

... A.M. Shipley S. Waitt J.R. Dzurisin D. Wood S.H. , 1981 , Areal distribution thickness, mass, volume, and grain-size of airfall ash from the six major eruptions of 1980 , in Lipman P.W. Mullineaux D.R. , eds ., The 1980 eruptions of Mount St. Helens, Washington...

..., had an estimated intensity between that of Mount St. Helens (Washington State, USA) and Pinatubo (Philippines) ( Caudron et al., 2015 ); the first stages were associated with an eruption column 26 km in height ( Kristiansen et al., 2015 ). Pumice lapilli samples were collected from the crater...

... 18, 1980, eruption of Mount St. Helens, 1: Melt composition and experimental phase equilibria: Journal of Geophysical Research , 90 , p. 2929 – 2947. 0091-7613(1998)v.26[0523:SEOOAM]2.0.CO;2 Streck M.J...

... ). Analysis of long-period seismic-waves excited by the May 18, (1980), eruption of Mount St. Helens—a terrestrial monopole , J. Geophys. Res. 87 , 5422 - 5432 . Kanamori H. Given J. W. Lay T. ( 1984 ). Analysis of seismic body waves excited by the Mount St.-Helens Eruption of May 18...

..., it would be unlikely that a large magma body would exist under a stratovolcano such as Mount Berlin. In other stratovolcanoes, such as Mount Saint Helens, geophysical and geochemical investigations suggest that eruptions are derived from very small bodies of melt that reside briefly in a small “holding...

... the Explosive Eruption of Mount St. Helens, Washington on 18 May 1980 Kentucky Earthquake, Ground Motion Values Obtained for the 27 July 1980 Sharpsburg, by Ronald Street--Erratum Khattri, K., M. Wyss, V. K Gaur, S. H. Saha, and V K. Bansal--Local Seismic Actlwty m the Region of the Assam Gap, Northeast Indm...

... because of the implications for modern volcanism. Studies in active volcanic arcs often reveal a general association between regional structures and the surficial location of volcanoes. For instance, Mount St. Helens is located at a small dextral offset where the regional fracture sets change orientation...

...) Washington. May 18, 1980 15h32m11.4s, 46.21°N, 122 19°W, focal depth about 4 km (SEA). Felt (V) at Yakima Felt (IV) m many parts of Washmgton and Oregon Associated with Mount St. Helens eruption (canvassed and field mvestlgated by USGS and press reports). Magnitude 4.7 (GS mb), 5.0 (GS ML), 5.2 (GS Ms...