scholarly journals A method for estimating intermediate and long-term risks from volcanic activity, with an example from Mount St. Helens, Washington

1982 ◽  
Author(s):  
C.G. Newhall
Keyword(s):  
Volcanic Activity ◽  
Mount St Helens

scholarly journals The rebirth and evolution of Bezymianny volcano, Kamchatka after the 1956 sector collapse

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Alina V. Shevchenko ◽  
Viktor N. Dvigalo ◽  
Thomas R. Walter ◽  
Rene Mania ◽  
Francesco Maccaferri ◽  
...  
Keyword(s):  
Growth Rate ◽  
Numerical Modeling ◽  
Volcanic Activity ◽  
Summit Crater ◽  
Sector Collapse ◽  
Average Growth Rate ◽  
Average Growth ◽  
Bezymianny Volcano ◽  
Lava Domes

Abstract Continued post-collapse volcanic activity can cause the rise of a new edifice. However, details of such edifice rebirth have not been documented yet. Here, we present 7-decade-long photogrammetric data for Bezymianny volcano, Kamchatka, showing its evolution after the 1956 sector collapse. Edifice rebirth started with two lava domes originating at distinct vents ~400 m apart. After 2 decades, activity became more effusive with vents migrating within ~200 m distance. After 5 decades, the activity focused on a single vent to develop a stratocone with a summit crater. We determine a long-term average growth rate of 26,400 m3/day, allowing us to estimate the regain of the pre-collapse size within the next 15 years. Numerical modeling explains the gradual vents focusing to be associated with loading changes, affecting magma pathways at depth. This work thus sheds light on the complex regrowth process following a sector collapse, with implications for regrowing volcanoes elsewhere.

A volcanologist's review of atmospheric hazards of volcanic activity: Fuego and Mount St. Helens

1983 ◽  
Vol 17 (1-4) ◽  
pp. 133-157 ◽  
Author(s):  
William I. Rose ◽  
Richard L. Wunderman ◽  
Mary F. Hoffman ◽  
Lisa Gale
Keyword(s):  
Volcanic Activity ◽  
Mount St Helens

scholarly journals Mapping Recent Fluctuations of Shoestring Glacier, Mount St. Helens (Abstract)

1986 ◽  
Vol 8 ◽  
pp. 203
Author(s):  
Melinda M. Brugman
Keyword(s):  
Volcanic Activity ◽  
Volcanic Eruptions ◽  
Aerial Photographs ◽  
Mass Balances ◽  
Mountain Glacier ◽  
Local Climate ◽  
Surficial Geology ◽  
Glacier Fluctuations ◽  
Glacier Terminus ◽  
Mount St Helens

The terminus position of Shoestring Glacier, Mount St. Helens, has pulsated over the last few centuries, generally following local climate trends, but the pattern of advance and retreat has been strongly modulated by effects of local volcanic activity. In this paper, I discuss the techniques employed to map and survey fluctuations in ice velocity, thickness, and terminus position of Shoestring Glacier. Solutions to major problems in acquiring and interpreting data peculiar to an active volcano are also explained. Results show that this steep mountain glacier responds quickly and dramatically to local environmental changes. The effects of volcanic activity are distinguished from internal instabilities and local climate change by combining information obtained using a variety of techniques, including field surveying, contour-mapping using stereo-aerial photographs, photo-documentation, and published historical accounts, In this paper I will focus attention on surveying and mapping conducted since 1979 at Shoestring Glacier, but will also discuss methods used to identify historic and “prehistoric” glacier fluctuations back to the early 1800s. The field survey was conducted at the glacier from mid-1979 to late 1983, during several eruptive episodes, major earthquakes, and covering winter and summer velocity and thickness changes. (Brugman and Post, 1980; Brugman and Meier, 1981). Coordinates of glacier velocity markers and the survey reference net were monitored with several different theodolites and electronic distance meters. In addition, topographic maps of Shoestring Glacier and vicinity were made for the years between 1979 and 1982, for the purpose of characterizing the drastic changes which occurred during the volcanic eruption of Mount St. Helens of May 18, 1980. The maps were constructed with 2 m contour intervals, using three sets of vertical aerial photographs. The difference between maps results in two plots showing the surficial changes caused by the volcanic field-checked against ground survey data on thickness change, using standard techniques. Overall, this study included monitoring glacier flow, configuration, and thickness changes at Shoestring Glacier since mid-1979, and also monitoring any changes in the local survey net due to ground deformation associated with nearby volcanic activity. In addition, photographic and written documentation of recent glacier fluctuations at Mount St. Helens was compiled from a variety of sources, which included local explorers, scientists, mountaineers, aviators, and historians. From this information, I was able to obtain the general pattern of Shoestring Glacier terminus fluctuations since the early 1900s. To extend the study further back in time, I also mapped the local surficial geology surrounding Shoestring Glacier using aerial photographs and ground studies. Because Mount St. Helens is a highly active, young volcano, a major problem was to distinguish glacier moraines, built during a recent ice advance, from volcanic levees built during passage of a recent lahar. Both lahar levees and glacier moraines exist along the glacier margin and most have been dissected and scoured by later mudflows. This study required the separate identification of glacial lag-till, from mudflow and rock avalanche debris. Comparison of depositional and erosional features generated by the several major lahars which decended over the Shoestring Glacier during the 1980 eruptions to pre-1980 surficial geology shows that glacier and lahar deposits are closely intermingled, but they can be distinguished on the basis of surface morphology obtained from aerial photographs, supported by field mapping of sedimentary structures. The dominant pre-1980 surficial deposits were laid down during a time of intense volcanism dating from 1800-1857, when the Shoestring Glacier was initially at its most advanced terminus position in its limited geologic record. During the early 1900s, several minor historic eruptions deposited ash and debris as distinctive englacial debris layers, which were well preserved within the glaciers on Mount St. Helens. Rock material deposited in the early to mid-1800s from glacier advances and volcanic eruptions can be distinguished from volcanic material deposited during the early 1900s because of the minor effect these later eruptions had on the glaciers of Mount St. Helens. This study shows that, over the last few centuries, repeated eruptions of Mount St. Helens have caused important changes in the mass balance of Shoestring Glacier. During several volcanic eruptions since 1800, the Shoestring and nearby glaciers have been deeply blanketed with rock ejecta and avalanche and mudflow debris, which could have increased the glacier mass balances. In contrast, the dominant effect of major volcanic eruptions on the Shoestring Glacier has led to strongly negative mass balances due to scouring, melting, and blasting away of glacier snow and ice. Deep incision of the glacier and its surrounding topography is clearly evident from the maps produced during this study, both during and before 1980. This melting and scouring occurred as pyroclastic flows and lahars swept down the glacier-filled canyon from the summit of the volcano and has probably occurred repeatedly since the canyon holding the Shoestring Glacier was first cut, approximately two thousand years ago. The eruption of Mount St. Helens on May 18, 1980, when the Shoestring Glacier was beheaded, deeply incised, and covered by volcanic ejecta and mudflow debris, is the most recent example of the highly variable environment in which the glacier continues to survive.

scholarly journals Origin of Pumice in Sediments from the Middle Okinawa Trough: Constraints from Whole-Rock Geochemical Compositions and Sr-Nd-Pb Isotopes

2019 ◽  
Vol 7 (12) ◽  
pp. 462
Author(s):  
Xue Fang ◽  
Zhigang Zeng ◽  
Siyi Hu ◽  
Xiaohui Li ◽  
Zuxing Chen ◽  
...  
Keyword(s):  
Volcanic Activity ◽  
Lower Crust ◽  
Late Quaternary ◽  
Okinawa Trough ◽  
Volcanic Rocks ◽  
The Okinawa Trough ◽  
Primitive Magma ◽  
The Indian Ocean ◽  
Lower Crustal

Frequent volcanic activity has occurred in the Okinawa Trough (OT) during the late Quaternary, which attracted much attention to the origin of volcanic rocks. Pumice collected from the seafloor has been extensively investigated, whereas few studies paid attention to the pumice in the sediment. The geochemical compositions of pumice preserved in sediments generally provide insight into past volcanic activity and regional magmatism. Here, we present major and trace element compositions and Sr-Nd-Pb isotope data, together with the established age framework for pumice samples recovered from sediment core S9 in the middle OT (MOT) to investigate their possible formation. Compositionally, the S9 pumice samples are dacite and are characterized by relatively higher Sr (87Sr/86Sr = 0.70480–0.70502) and Pb (206Pb/204Pb = 18.321-18.436, 207Pb/204Pb = 15.622–15.624, and 208Pb/204Pb = 38.52–38.63) and lower Nd (143Nd/144Nd = 0.51272–0.51274) isotope compositions than basalts from the MOT. The geochemical compositions of pumice clasts from different layers of core S9 display no temporal variation trends and vary within narrow ranges. On the basis of the geochemical characteristics of S9 pumice samples, we infer that the parent magma of these samples might generate from hybrid magma through an extensive fractional crystallization process. The Indian Ocean MORB-type mantle was first metasomatized by the subducted Philippine Sea sediments to form the primitive magma; then, followed by assimilation of a small amount of lower crustal component occurred in the lower crust. The long-term magmatism and relatively consistent isotopic compositions indicate that a magma chamber might have existed in the lower crust of the MOT between 11.22 and 12.96 cal. ka BP.

scholarly journals Mapping Recent Fluctuations of Shoestring Glacier, Mount St. Helens (Abstract)

1986 ◽  
Vol 8 ◽  
pp. 203-203
Author(s):  
Melinda M. Brugman
Keyword(s):  
Volcanic Activity ◽  
Volcanic Eruptions ◽  
Aerial Photographs ◽  
Mass Balances ◽  
Mountain Glacier ◽  
Local Climate ◽  
Surficial Geology ◽  
Glacier Fluctuations ◽  
Glacier Terminus ◽  
Mount St Helens

The terminus position of Shoestring Glacier, Mount St. Helens, has pulsated over the last few centuries, generally following local climate trends, but the pattern of advance and retreat has been strongly modulated by effects of local volcanic activity. In this paper, I discuss the techniques employed to map and survey fluctuations in ice velocity, thickness, and terminus position of Shoestring Glacier. Solutions to major problems in acquiring and interpreting data peculiar to an active volcano are also explained. Results show that this steep mountain glacier responds quickly and dramatically to local environmental changes. The effects of volcanic activity are distinguished from internal instabilities and local climate change by combining information obtained using a variety of techniques, including field surveying, contour-mapping using stereo-aerial photographs, photo-documentation, and published historical accounts, In this paper I will focus attention on surveying and mapping conducted since 1979 at Shoestring Glacier, but will also discuss methods used to identify historic and “prehistoric” glacier fluctuations back to the early 1800s.The field survey was conducted at the glacier from mid-1979 to late 1983, during several eruptive episodes, major earthquakes, and covering winter and summer velocity and thickness changes. (Brugman and Post, 1980; Brugman and Meier, 1981). Coordinates of glacier velocity markers and the survey reference net were monitored with several different theodolites and electronic distance meters. In addition, topographic maps of Shoestring Glacier and vicinity were made for the years between 1979 and 1982, for the purpose of characterizing the drastic changes which occurred during the volcanic eruption of Mount St. Helens of May 18, 1980. The maps were constructed with 2 m contour intervals, using three sets of vertical aerial photographs. The difference between maps results in two plots showing the surficial changes caused by the volcanic field-checked against ground survey data on thickness change, using standard techniques. Overall, this study included monitoring glacier flow, configuration, and thickness changes at Shoestring Glacier since mid-1979, and also monitoring any changes in the local survey net due to ground deformation associated with nearby volcanic activity.In addition, photographic and written documentation of recent glacier fluctuations at Mount St. Helens was compiled from a variety of sources, which included local explorers, scientists, mountaineers, aviators, and historians. From this information, I was able to obtain the general pattern of Shoestring Glacier terminus fluctuations since the early 1900s.To extend the study further back in time, I also mapped the local surficial geology surrounding Shoestring Glacier using aerial photographs and ground studies. Because Mount St. Helens is a highly active, young volcano, a major problem was to distinguish glacier moraines, built during a recent ice advance, from volcanic levees built during passage of a recent lahar. Both lahar levees and glacier moraines exist along the glacier margin and most have been dissected and scoured by later mudflows. This study required the separate identification of glacial lag-till, from mudflow and rock avalanche debris. Comparison of depositional and erosional features generated by the several major lahars which decended over the Shoestring Glacier during the 1980 eruptions to pre-1980 surficial geology shows that glacier and lahar deposits are closely intermingled, but they can be distinguished on the basis of surface morphology obtained from aerial photographs, supported by field mapping of sedimentary structures. The dominant pre-1980 surficial deposits were laid down during a time of intense volcanism dating from 1800-1857, when the Shoestring Glacier was initially at its most advanced terminus position in its limited geologic record. During the early 1900s, several minor historic eruptions deposited ash and debris as distinctive englacial debris layers, which were well preserved within the glaciers on Mount St. Helens. Rock material deposited in the early to mid-1800s from glacier advances and volcanic eruptions can be distinguished from volcanic material deposited during the early 1900s because of the minor effect these later eruptions had on the glaciers of Mount St. Helens.This study shows that, over the last few centuries, repeated eruptions of Mount St. Helens have caused important changes in the mass balance of Shoestring Glacier. During several volcanic eruptions since 1800, the Shoestring and nearby glaciers have been deeply blanketed with rock ejecta and avalanche and mudflow debris, which could have increased the glacier mass balances. In contrast, the dominant effect of major volcanic eruptions on the Shoestring Glacier has led to strongly negative mass balances due to scouring, melting, and blasting away of glacier snow and ice. Deep incision of the glacier and its surrounding topography is clearly evident from the maps produced during this study, both during and before 1980. This melting and scouring occurred as pyroclastic flows and lahars swept down the glacier-filled canyon from the summit of the volcano and has probably occurred repeatedly since the canyon holding the Shoestring Glacier was first cut, approximately two thousand years ago. The eruption of Mount St. Helens on May 18, 1980, when the Shoestring Glacier was beheaded, deeply incised, and covered by volcanic ejecta and mudflow debris, is the most recent example of the highly variable environment in which the glacier continues to survive.

scholarly journals Gas-Derived Aerosol in Central Antarctic Snow and Ice: the Case of Sulphuric and Nitric Acids

1982 ◽  
Vol 3 ◽  
pp. 71-76 ◽  
Author(s):  
Robert J. Delmas ◽  
Jean Marc Barnola ◽  
Michel Legrand
Keyword(s):  
Volcanic Activity ◽  
Mean Values ◽  
Sulphate Concentration ◽  
Antarctic Snow ◽  
Different Depths ◽  
The Mean ◽  
Probable Origin ◽  
Snow And Ice

New results concerning the concentration of sulphate (SO4) and nitrate (NO3) in Antarctic snow and ice are presented. At Dome C, 10-year mean values and detailed studies (more than one sample a−1) were done at different depths corresponding to ages from 0 to 23 ka BP. Global volcanic activity strongly disturbs profiles of sulphate concentration for periods of a few years. Long-term fluctuations are found to be weak for both anions. The mean values obtained for acidity agree satisfactorily with the values for sulphate and nitrate. Finally, we examine the probable origin of these gas-derived aerosols in Antarctica.

scholarly journals Chapter 26 Consequences of long-term volcanic activity for essential services in Montserrat: challenges, adaptations and resilience

2014 ◽  
Vol 39 (1) ◽  
pp. 471-488 ◽  
Author(s):  
V. Sword-Daniels ◽  
T. M. Wilson ◽  
S. Sargeant ◽  
T. Rossetto ◽  
J. Twigg ◽  
...  
Keyword(s):  
Volcanic Activity ◽  
Essential Services

scholarly journals Global warming and greenhouse gases

2006 ◽  
Vol 4 (1) ◽  
pp. 45-55 ◽  
Author(s):  
Dragoljub Belic
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Greenhouse Gases ◽  
Volcanic Activity ◽  
Solar Irradiance ◽  
Climate System ◽  
Orbital Parameters ◽  
Natural Processes ◽  
Earth’S Climate

Global warming or Climate change refers to long-term fluctuations in temperature, precipitation, wind, and other elements of the Earth's climate system. Natural processes such as solar-irradiance variations, variations in the Earth's orbital parameters, and volcanic activity can produce variations in climate. The climate system can also be influenced by changes in the concentration of various gases in the atmosphere, which affect the Earth's absorption of radiation.

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