Results 121 to 130 of about 1,217 (152)

Total grain-size distribution and volume of tephra-fall deposits

Bulletin of Volcanology, 2005
On 17 June 1996, Ruapehu volcano, New Zealand, produced a sustained andesitic sub-Plinian eruption, which generated a narrow tephra-fall deposit extending more than 200 km from the volcano. The extremely detailed data set from this eruption allowed methods for the determination of total grain-size distribution and volume of tephra-fall deposits to be ...
Costanza Bonadonna, Bruce F Houghton, Bonadonna C   +2 more
exaly   +4 more sources

Plinian and co-ignimbrite tephra fall from the

Bulletin of Volcanology, 1989
A study of pyroclastic deposits from the 1815 Tambora eruption reveals two distinct phases of activity, i.e., four initial tephra falls followed by generation of pyroclastic flows and the production of major co-ignimbrite ash fall. The first explosive event produced minor ash fall from phreatomagmatic explosions (F-1 layer).
Steven Carey, Sigurdsson Haraldur, Carey Steven   +2 more
exaly   +4 more sources

Sedimentation of tephra by volcanic plumes. Part 2: controls on thickness and grain-size variations of tephra fall deposits

Bulletin of Volcanology, 1992
A model for sedimentation from turbulent suspensions predicts that tephra concentration decreases exponentially with time in an ascending volcanic column and in the overlying umbrella cloud. For grain-size distributions typical of plinian eruptions application of the model predicts for thickness variations in good agreement with the exponential ...
R S J Sparks, S N Carey, Sparks R S J
exaly   +4 more sources

A model for the numerical simulation of tephra fall deposits

Journal of Volcanology and Geothermal Research, 2005
Abstract A simple semianalytical model to simulate ash dispersion and deposition produced by sustained Plinian and sub-Plinian eruption columns based on the 2D advection–dispersion equation was applied. The eruption column acts as a vertical line source with a given mass distribution and neglects the complex dynamics within the eruption column. Thus,
T. Pfeiffer, A. Costa, G. Macedonio
openaire   +2 more sources

Agricultural vulnerability to tephra fall impacts. [PDF]

, 2015
Understanding agricultural impact from tephra hazards and their causal mechanisms is vital when developing mitigation and recovery strategies. It is well documented that tephra can impact agricultural systems. However, forecasting likely impacts has been challenging and focused on creating generalised models where impacts typically increase with tephra
Craig, Heather M.
openaire   +3 more sources

A varve-based calibration of the Bridge River tephra fall

Canadian Journal of Earth Sciences, 1995
A 1 cm thick layer of Bridge River tephra is preserved in a core of varved lake sediments recovered from Hector Lake, Alberta. The varve sequence extends from the core top to well below the tephra layer and has bseen calibrated to calendar years. A varve count yields a calendar age of 2332 BP for the ash layer, with a potential error of about ±50 ...
Eric M. Leonard
openaire   +2 more sources

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Three empirical methods for the calculation of distal volume of tephra-fall deposits

Journal of Volcanology and Geothermal Research, 2005
Abstract Three empirical methods for the calculation of distal tephra-fall volumes are presented and tested. The three methods allow calculation of approximate distal tephra-fall volumes under different conditions and abundances of field data. All methods use proximal data to extrapolate the distal situation. They are based on: i) shape and dispersal
Roberto Sulpizio
exaly   +2 more sources

Probabilistic tephra fall simulation for the Auckland Region, New Zealand

Journal of Volcanology and Geothermal Research, 2006
Abstract The Auckland Region, New Zealand is at significant risk from tephra falls originating both from the local Auckland Volcanic Field (AVF) and several distant, large-volume centres. We use geological data and observations of historical eruptions to develop a catalogue of simulated tephra dispersal patterns for the Auckland Region, using the ...
Tony Hurst
exaly   +2 more sources

Tephra fall hazard for the Neapolitan area

, 2015
Tephra fall hazard for the Neapolitan areaPublished239-2486V.
Marzocchi W., Selva J., Costa A., Sandri L., Tonini R., Macedonio G.   +5 more
core   +4 more sources

Analysis of the 2020 Taal Volcano tephra fall deposits from crowdsourced information and field data

Bulletin of Volcanology, 2022
International audienceAfter 43 years of dormancy, Taal Volcano violently erupted in January 2020 forming a towering eruption plume. The fall deposits covered an area of 8605 km2, which includes Metro Manila of the National Capital Region of the ...
A M F Lagmay, Lucia Gurioli, B Van Wyk De Vries   +2 more
exaly   +2 more sources