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Quantitative Shape Measurements Of Distal Volcanic Ash, William I. Rose, Colleen M. Riley, Gregg J. Bluth

Department of Geological and Mining Engineering and Sciences Publications

Large-scale volcanic eruptions produce fine ash (< 200 μm) which has a long atmospheric residence time (1 hour or more) and can be transported great distances from the volcanic source, thus, becoming a hazard to aircraft and public health. Ash particles have irregular shapes, so data on particle shape, size, and terminal velocities are needed to understand how the irregular-shaped particles affect transport processes and radiative transfer measurements. In this study, a methodology was developed to characterize particle shapes, sizes , and terminal velocities for three ash samples of different compositions. The shape and size of 2,500 particles from 1) distal fallout (~100 km) of the October 14, 1974 Fuego eruption (basaltic), 2) the secondary maxima (~250 km) of the August 18, 1992 Spurr eruption (andesitic), and 3) the Miocene Ash Hollow member, Nebraska (rhyolitic) were measured using image analysis techniques. Samples were sorted into 10 to 19 terminal velocity groups (0.6-59.0 cm/s) using an air elutriation device. Grain size distributions for the samples were measured using laser diffraction. Aspect ratio, feret diameter, and perimeter measurements were found to be the most useful descriptors of how particle shape affects terminal velocity. These measurement values show particle shape differs greatly from a sphere (commonly used in models and algorithms). The diameters of ash particles were 10-120% larger than ideal spheres at the same terminal velocity, indicating that irregular particle shape greatly increases drag. Gas-adsorption derived surface areas are 1 to 2 orders of magnitude higher than calculated surface areas based on measured dimensions and simple geometry, indicating that particle shapes are highly irregular. Correction factors for surface area were derived from the ash sample measurements so that surface areas calculated by assuming spherical particle shapes can be corrected to reflect more realistic values.

Retrieval Of Mass And Sizes Of Particles In Sandstorms Using Two Modis Ir Bands: A Case Study Of April 7 2001 Sandstorm In China, Yingxin Gu, William I. Rose, Gregg J. Bluth

Department of Geological and Mining Engineering and Sciences Publications

A thermal infrared remote sensing retrieval method developed by Wen and Rose [1994], which retrieves particle sizes, optical depth, and total masses of silicate particles in the volcanic cloud, was applied to an April 07, 2001 sandstorm over northern China, using MODIS. Results indicate that the area of the dust cloud observed was 1.34 million km2, the mean particle radius of the dust was 1.44 μm, and the mean optical depth at 11 μm was 0.79. The mean burden of dust was approximately 4.8 tons/km2 and the main portion of the dust storm on April 07, 2001 contained 6.5 million …

Numerical And Granulometric Approaches To Geophysical Granular Flows , Sébastien Dartevelle

Dissertations, Master's Theses and Master's Reports - Open

Volcanic ash clouds can be fed by an upward-directed eruption column (Plinian column) or by elutriation from extensive pyroclastic-flows (coignimbrite cloud). For large-scale eruptions, there is considerable uncertainty about which mechanism is dominant. Here we analyze in a novel way a comprehensive grainsize database for pyroclastic deposits. We demonstrate that the Mount Pinatubo climactic eruption deposits were substantially derived from coignimbrite clouds, and not only by a Plinian cloud as generally thought. Coignimbrite ash-fall deposits are much richer in breathable <10 m ash (5–25 wt%) than pure Plinian ash at most distances from the source volcano. We also show that coignimbrite ash clouds, as at Pinatubo, are expected to be more water rich than Plinian clouds, leading to removal of more HCl prior to stratospheric injection, thereby reducing their atmospheric impact.

Observations Of Volcanic Clouds In Their First Few Days Of Atmospheric Residence: The 1992 Eruptions Of Crater Peak, Mount Spurr Volcano, Alaska, William I. Rose, Gregg J. Bluth, David J. Schneider, Gerald G. J. Ernst, Colleen M. Riley, Lydia J. Henderson, Robert G. Mcgimsey

Department of Geological and Mining Engineering and Sciences Publications

Satellite SO2 and ash measurements of Mount Spurr’s three 1992 volcanic clouds are compared with ground‐based observations to develop an understanding of the physical and chemical evolution of volcanic clouds. Each of the three eruptions with ratings of volcanic explosivity index three reached the lower stratosphere (14 km asl), but the clouds were mainly dispersed at the tropopause by moderate to strong (20–40 m/s) tropospheric winds. Three stages of cloud evolution were identified. First, heavy fallout of large (>500 μm) pyroclasts occurred close to the volcano (vent) during and immediately after the eruptions, and the cloud resembled an advected …

Use Of Goes Thermal Infrared Imagery For Eruption Scale Measurements, Soufrière Hills, Montserrat, William I. Rose, Gari C. Mayberry

Department of Geological and Mining Engineering and Sciences Publications

GOES two-band IR data are used to estimate the magnitude of small eruption clouds (ash; <∼10⁵ tonnes of fine [1–25 µm in diameter] ash, and 5–15 km asl). The method is demonstrated on clouds from Soufrière Hills Volcano, Montserrat in 1997–99. The clouds in early 1999 were much smaller, were generally emplaced lower in the atmosphere and contained an order of magnitude less fine ash than 1997 clouds generated during the most intense phase of the eruption to date. Although GOES has an excellent capability for large eruption clouds, its use for smaller eruptions like Montserrat highlights several shortcomings, including …

Comparison Of Toms And Avhrr Volcanic Ash Retrievals From The August 1992 Eruption Of Mt. Spurr, N. A. Krotkov, O. Torres, C. Seftor, A. J. Krueger, A. Kostinski, William I. Rose, Gregg J. Bluth, D. Schneider, S. J. Schaefer

Department of Geological and Mining Engineering and Sciences Publications

On August 19, 1992, the Advanced Very High Resolution Radiometer (AVHRR) onboard NOAA-12 and NASA's Total Ozone Mapping Spectrometer (TOMS) onboard the Nimbus-7 satellite simultaneously detected and mapped the ash cloud from the eruption of Mt. Spurr, Alaska. The spatial extent and geometry of the cloud derived from the two datasets are in good agreement and both AVHRR split window IR (11–12µm brightness temperature difference) and the TOMS UV Aerosol Index (0.34–0.38µm ultraviolet backscattering and absorption) methods give the same range of total cloud ash mass. Redundant methods for determination of ash masses in drifting volcanic clouds offer many advantages …

Early Evolution Of A Stratospheric Volcanic Eruption Cloud As Observed With Toms And Avhrr, David J. Schneider, William I. Rose, Larry R. Coke, Gregg J. Bluth, Ian E. Sprod, Arlin J. Krueger

Department of Geological and Mining Engineering and Sciences Publications

This paper is a detailed study of remote sensing data from the total ozone mapping spectrometer (TOMS) and the advanced very high resolution radiometer (AVHRR) satellite detectors, of the 1982 eruption of El Chichón, Mexico. The volcanic cloud/atmosphere interactions in the first four days of this eruption were investigated by combining ultraviolet retrievals to estimate the mass of sulfur dioxide in the volcanic cloud [Krueger et al., 1995] with thermal infrared retrievals of the size, optical depth, and mass of fine-grained (1–10 μm radius) volcanic ash [Wen and Rose, 1994]. Our study provides the first direct evidence of gravitational separation …

Stratospheric Loading Of Sulfur From Explosive Volcanic Eruptions, Gregg J. Bluth, William I. Rose, Ian E. Sprod, Arlin J. Krueger

Department of Geological and Mining Engineering and Sciences Publications

This paper is an attempt to measure our understanding of volcano/atmosphere interactions by comparing a box model of potential volcanogenic aerosol production and removal in the stratosphere with the stratospheric aerosol optical depth over the period of 1979 to 1994. Model results and observed data are in good agreement both in magnitude and removal rates for the two largest eruptions, El Chicho´n and Pinatubo. However, the peak of stratospheric optical depth occurs about nine months after the eruptions, four times longer than the model prediction, which is driven by actual SO2 measurements. For smaller eruptions, the observed stratospheric perturbation is …

Detection Of Volcanic Ash Clouds From Nimbus 7/Total Ozone Mapping Spectrometer, C. J. Seftor, N. C. Hsu, J. R. Herman, P. K. Bhartia, O. Torres, William I. Rose, David J. Schneider, N. Krotkov

Department of Geological and Mining Engineering and Sciences Publications

Measured radiances from the Version 7 reprocessing of the Nimbus 7/total ozone mapping spectrometer (TOMS) 340- and 380-nm channels are used to detect absorbing particulates injected into the atmosphere after the El Chichon eruption on April 4, 1982. It is shown that while the single-channel reflectivity determined from the 380-nm channel is able to detect clouds and haze composed of nonabsorbing aerosols, the spectral contrast between the 340- and 380-nm channels is sensitive to absorbing particulates such as volcanic ash, desert dust, or smoke from biomass burning. In this paper the spectral contrast between these two channels is used to …

Remote Sensing Of Volcanic Ash Clouds Using Special Sensor Microwave Imager Data, David J. Delene, William I. Rose, Norman C. Grody

Department of Geological and Mining Engineering and Sciences Publications

Measurements from the satellite-based special sensor microwave imager (SSM/I) were used to collect passive microwave radiation (19–85 GHz) for the August 19, 1992 (UT date), Crater Peak/Spurr volcanic cloud. This eruption was also imaged by a ground-based C-band radar system at Kenai, Alaska, 80 km away, and by the thermal infrared channels of the polar-orbiting advanced very high resolution radiometer (AVHRR). The SSM/I sensor detects scattering of Earth-emitted radiation by millimeter size volcanic ash particles. The size of ash particles in a volcanic ash cloud can be estimated by comparing the scattering at different microwave frequencies. The mass of particles …

Measurements Of The Complex Dielectric Constant Of Volcanic Ash From 4 To 19 Ghz, R. J. Adams, Warren F. Perger, William I. Rose, A. Kostinski

Department of Geological and Mining Engineering and Sciences Publications

Dielectric data in volcanic ash at weather radar wavelengths (centimeter range) are extremely sparse and are crucial for radar sensing of ash clouds and for imaging of volcanic terrains. This study extends previous data to include a wavelength range of 1.5–7.5 cm and volcanic ash compositions of 50–75% silica. The real part of the complex permittivity, ε′, of volcanic ash is 6 ± 0.5 (1σ) for all wavelengths. The imaginary part, ε″, ranges from 0.08 to 0.27. Both ε′ and ε″ show higher values at lower SiO2 concentration. It is safe to assume in any weather radar applications that the …

Retrieval Of Sizes And Total Masses Of Particles In Volcanic Clouds Using Avhrr Bands 4 And 5, Shiming Wen, William I. Rose

Department of Geological and Mining Engineering and Sciences Publications

The advanced very high resolution radiometer (AVHRR) sensor on polar orbiting NOAA satellites can discriminate between volcanic clouds and meteorological clouds using two-band data in the thermal infrared. This paper is aimed at developing a retrieval of the particle sizes, optical depth, and total masses of particles from AVHRR two-band data of volcanic clouds. Radiative transfer calculations are used with a semi-transparent cloud model that is based on assumptions of spherical particle shape, a homogeneous underlying surface, and a simple thin cloud parallel to the surface. The model is applied to observed AVHRR data from a 13-hour old drifting cloud …

Goes Imagery Fills Gaps In Montserrat Volcanic Cloud Observations, Mark A. Davies, William I. Rose

Department of Geological and Mining Engineering and Sciences Publications

GOES satellite imagery offers great potential to lessen the risk of volcanic ash clouds to aviation, and the situation at Montserrat in the Caribbean is providing the proof. Many transatlantic, commercial, and private aircraft use airspace around Montserrat, where the Soufriere Hills Volcano has been erupting since 1995.

Worldwide over the last 15 years, more than 80 airplanes have reported encountering volcanic ash along flight paths. Encounters cannot be avoided because onboard radar cannot detect fine-grained ash particles—those with a radius of 15 microns or less. In recent years volcanic cloud encounters are estimated to have caused hundreds of millions …

Common Characteristics Of Paired Volcanoes In Northern Central America, S. P. Halsort, William I. Rose

Department of Geological and Mining Engineering and Sciences Publications

Four pairs of active volcanoes along the northern Central American volcanic front have erupted basalt-andesite magmas that show consistent intrapair behavioral and compositional differences. These differences are found in records of volcanic activity and complete major and minor element data on over 200 samples. From northwest to southeast along the volcanic front the four volcano pairs are Cerro Quemado-Santa María, Tolimán-Atitlán, Acatenango-Fuego, and Santa Ana-Izalco. The volcano pair relations help explain compositional differences, apart from those reflecting variation in crustal thickness of about 15 km along the volcanic front, providing insight into across-arc variations and closely spaced subvolcanic plumbing systems. …

Direct Rate Measurements Of Eruption Plumes At Augustine Volcano: A Problem Of Scaling And Uncontrolled Variables, William I. Rose, Grant Heiken, Kenneth Wohletz, Dean Eppler, Sumner Barr, Theresa Miller, Raymond L. Chuan, R. B. Symonds

Department of Geological and Mining Engineering and Sciences Publications

The March–April 1986 eruption of Augustine Volcano, Alaska, provided an opportunity to directly measure the flux of gas, aerosol, and ash particles during explosive eruption. Most previous direct measurements of volcanic emission rates are on plumes from fuming volcanoes or on very small eruption clouds. Direct measurements during explosive activity are needed to understand the scale relationships between passive degassing or small eruption plumes and highly explosive events. Conditions on April 3, 1986 were ideal: high winds, clear visibility, moderate activity. Three measurements were made: 1) an airborne correlation spectrometer (Cospec) provided mass flux rates of SO₂; 2) …

Dynamic Deformation Of Volcanic Ejecta From The Toba Caldera: Possible Relevance To Cretaceous/Tertiary Boundary Phenomena, Neville L. Carter, Charles B. Officer, Craig A. Chesner, William I. Rose

Department of Geological and Mining Engineering and Sciences Publications

Plagioclase and biotite phenocrysts in ignimbrites erupted from the Toba caldera, Sumatra, show microstructures and textures indicative of shock stress levels higher than 10 GPa. Strong dynamic deformation has resulted in intense kinking in biotite and, with increasing shock intensity, the development in plagioclase of planar features, shock mosaicism, incipient recrystallization, and possible partial melting. Microstructures in quartz indicative of strong shock deformation are rare, however, and many shock lamellae, if formed, may have healed during post-shock residence in the hot ignimbrite; they might be preserved in ash falls. Peak shock stresses from explosive silicic volcanism and other endogenous processes …

Sulfur Dioxide And Particles In Quiescent Volcanic Plumes From Poás, Arenal, And Colima Volcanos, Costa Rica And Mexico, T. Casadevall, William I. Rose, William H. Fuller, William H. Hunt, Mark A. Hart, Jarvis L. Moyers, David C. Woods, Raymond L. Chuan, James P. Friend

Department of Geological and Mining Engineering and Sciences Publications

Measurements of SO₂ emission rates and concentrations and of particle distribution, size, shape, and composition were made in quiescent volcanic plumes emitted into the troposphere from Poás and Arenal volcanos, Costa Rica, and Colima volcano, Mexico. SO₂ emission rates were 700±180 metric tons per day (t/d) for Poás, 210±30 t/d for Arenal, and 320±50 t/d for Colima. The concentrations of SO₂ calculated from the COSPEC/lidar data were 5–380 ppb. Concentrations of SO₂measured directly by flame photometry were 10–250 ppb. Particles collected in the plumes with a quartz crystal microbalance impactor were mostly less than 3 …

Amatitlan, An Actively Resurging Cauldron 10 Km South Of Guatemala City, Richard L. Wunderman, William I. Rose

Department of Geological and Mining Engineering and Sciences Publications

A 14×16 km diameter collapse caldera has been recognized 10 km south of Guatemala City, Guatemala. The caldera is north of the presently active volcano Pacaya and west of Agua, a large stratovolcano. The caldera was not previously recognized because its eastern and western margins coincide with faults that outline the Guatemala City graben and because the northern margin of the caldera is buried by pyroclastic rocks. The existence of the northern caldera margin is now established by gravity data and a variety of geological observations including circumferential faults, hot springs, well-log data, and lithological changes in sedimentary rocks. A …

Estimating Particle Sizes, Concentrations, And Total Mass Of Ash In Volcanic Clouds Using Weather Radar, David M. Harris, William I. Rose

Department of Geological and Mining Engineering and Sciences Publications

Observations of the March 19, 1982 ash eruption of Mount St. Helens, made by the National Weather Service (NWS, Portland, Oregon) on 5-cm radar, were used to estimate the volume of the ash cloud (2000 ±500 km³), the concentration of ash (0.2–0.6 g m⁻³). and the total mass of ash erupted (3–10×10¹¹ g). The position of the cloud was also tracked by radar. Particle sizes in the ash cloud were estimated from settling velocities suggested by decreases in maximum ash cloud height with time as it moved away from the volcano. The March 19, 1982 …

Research On Atmospheric Volcanic Emissions: An Overview, James P. Friend, Alan R. Bandy, Jarvis L. Moyers, William H. Zoller, Richard E. Stoiber, Arnold L. Torres, William I. Rose, M. Patrick Mccormick, David C. Woods

Department of Geological and Mining Engineering and Sciences Publications

The project "Research on Atmospheric Volcanic Emissions" is a unique effort by NASA and university scientists to investigate the detailed chemical nature of plumes from volcanic eruptions. The major goals of the project are to: 1) understand the impact major eruptions will have on atmospheric chemistry processes, 2) understand the importance of volcanic emissions in the atmospheric geochemical cycles of selected species, 3) use knowledge of the plume chemical composition to diagnose and predict magmatic processes. Project RAVE'S first mission used the NASA Lockheed Orion P-3 outfitted with equipment to measure concentrations of the gases SO₂, OCS, H …

Water-Soluble Material On Aerosols Collected Within Volcanic Eruption Clouds, David B. Smith, Robert A. Zielinski, William I. Rose, B. J. Huebert

Department of Geological and Mining Engineering and Sciences Publications

In February and March of 1978, filter samplers mounted on an aircraft were used to collect the aerosol fraction of the eruption clouds from three active Guatemalan volcanoes (Fuego, Pacaya, and Santiaguito). The samples were collected on Teflon (Fluoropore) filters with a nominal pore diameter of 0.5μm. The mass of air sampled by the filters ranged from 0.15 to 6.6 kg. The particulate material collected consisted of fragments of angular silicate ash and droplets of what is interpreted as dilute H₂SO₄ and HCl. After collection of the samples, each filter was rinsed with 60 ml of distilled-deionized …

Small Particles In Plumes Of Mount St. Helens, William I. Rose, Raymond L. Chuan, D. C. Woods

Department of Geological and Mining Engineering and Sciences Publications

Particles in the size range of 0.1–25 micrometers were sampled by aircraft carrying a quartz crystal microcascade in the Mount St. Helens plume on three dates in August and September 1980. Two of the sampling dates represented ‘typical’ emissions of the volcano between plinian eruptions. One sampling flight was made 1–4 hours before the small plinian eruption of August 7, 1980, when the plume had become discontinuous and visibly darker. Size distributions were determined, and individual particles were studied by using scanning electron microscopy. The plume sampled on August 7, before the eruption, contained mainly approximately 2 micrometer diameter silicic …

Emission Rates Of Co2 From Plume Measurements., D. M. Harris, M. Sato, T. J. Casadevall, William I. Rose, T. J. Bornhorst

Michigan Tech Publications

Most of the CO2 that emanated from Mount St. Helens became part of the gas plume as it moved away from the volcano. An airborne technique was developed for continuous sampling and infrared analysis for CO2 in the plume. The CO2-emission rates were determined by measuring the area, the horizontal velocity, and the CO2 concentration anomaly in vertical cross sections of the plume The emission rate varied from 2100 t/day to about 22 000 t/day.-from Author

Radar Observations Of Ash Eruptions, D. M. Harris, William I. Rose, R. Roe, M. R. Thompson

Michigan Tech Publications

Radar systems located at Portland, Oreg., Seattle, Wash., and near Spokane, Wash., have been used extensively for observations of ash clouds from explosive volcanic eruptions at Mount St. Helens during 1980. Eruption clouds are composed of silicate particles and are therefore detectable by radar. Radar observations can be made at night and in overcast weather when conventional observations of eruptions are difficult.-from Authors

Determination Of The Total Grain Size Distribution In A Vulcanian Eruption Column, And Its Implications To Stratospheric Aerosol Perturbation, P. J. Murrow, William I. Rose, S. Self

Department of Geological and Mining Engineering and Sciences Publications

Grain size analysis of samples representing all sampleable portions of the airfall deposit produced by the Fuego volcano in Guatemala on 14 October 1974 form the basis for estimating the total grain size distribution of tephra from this eruption. The region enclosed by each isopach has a particular average grain size distribution which can be weighted proportionally to its percentage volume. The grain size of pyroclastic avalanche deposits produced during the eruption are also included. The total grain size distribution calculated as a sum of weighted distributions has a median grain size of 0.8∅ (0.6mm) and a sorting coefficient (σ∅) …

Atmospheric Implications Of Studies Of Central American Volcanic Eruption Clouds, R. D. Cadle, A. L. Lazrus, B. J. Huebert, L. E. Heidt, William I. Rose, D. C. Woods, Raymond L. Chuan, Richard E. Stoiber, D. B. Smith, Robert A. Zielinski

Department of Geological and Mining Engineering and Sciences Publications

During February 1978 a group of scientists from the National Center for Atmospheric Research, several colleges and universities, the U.S. Geological Survey, and NASA used a specially equipped Beech Queen Air aircraft to make 11 sampling flights in Guatemala through the eruption clouds from the volcanoes Pacaya, Fuego, and Santiguito. Measurements were made of SO₄²⁻, SO₂, HCl, HF, and 11 cations that were in water-soluble form, on samples collected by a specially designed filter pack. Particle size distributions were obtained with a piezoelectric cascade impactor, and the particles were identified by energy dispersive X ray …

The 1966 Eruption Of Izalco Volcano, El Salvador, William I. Rose, Richard E. Stoiber

Department of Geological and Mining Engineering and Sciences Publications

During October–November 1966 900,000 m³ of olivine basalt flowed from the flank of Izalco volcano, El Salvador. The total heat energy was approximately 10¹⁵ calories. No measurable changes in gravity occurred at stations on the active cone between August 1964 and August 1967. In the summit crater fumaroles have surface temperatures as high as 540°C. The cooling rate of these fumaroles was 18°C/yr before the eruption and 45°C/yr after. Yearly temperature cycles due to wet and dry seasons are superimposed on the general cooling trend. The rate of gas emission at four fumaroles in November 1967 was 86 …