[PDF] Probing Magma Reservoirs To Improve Volcano Forecasts eBook

Author : Brandon Schmandt
Publisher :
Page : 21 pages
File Size : 29,86 MB
Release : 2019
Category : Magmas
ISBN :

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Since 1.25 Ma, three volcanic systems in the western U.S. Cordillera hosted rhyolitic eruptions of greater than or equal to 300 km3 dense rock equivalent creating the Yellowstone (0.63 Ma), Long Valley (0.76 Ma), and Valles (1.25 Ma) calderas. Their similar time scales since caldera-forming eruptions and rich histories of seismic research motivate a review of seismic constraints on the modern magma reservoirs beneath these calderas from the uppermost mantle to the upper crust. Across the Cordillera upper mantle seismic velocities are generally below the continental average and each of the calderas is underlain by exceptionally low velocities consistent with the presence of mantle melt, greater than or equal to 3%. Concentrated upper mantle low-velocity anomalies are found beneath the eastern Snake River plain southwest of Yellowstone caldera and beneath Long Valley caldera. Valles caldera is located above a broadly distributed low-velocity anomaly associated with the Rio Grande Rift and Jemez volcanic lineament. At lower crustal depths potential magma reservoirs exhibit weaker seismic velocity anomalies and greater variability among the results of different tomographic inversion methods compared to shallower depths. At middle-to-upper crustal depths, ~5?15 km, seismic tomography provides evidence of magmatic reservoirs beneath all three calderas, and scattered wave imaging supports sharp upper, lateral, and/or lower boundaries of each inferred magma reservoir. Estimates of average melt fractions in these reservoirs vary from ~9?23% based on recent tomography, with localized melt fraction estimates as high as ~30?60% based on sharp interfaces detected by scattering and ray bending analyses. The wide range of inferred melt fractions likely results from contrasting sensitivities of different seismic imaging methods combined with spatially heterogeneous melt fractions and uncertainties in mapping seismic velocities to silicate melt fractions. Seismic radial anisotropy beneath Yellowstone and Long Valley calderas indicates that middle-to-upper crustal reservoirs are organized as sill complexes with relatively crystal-poor and crystal-rich layers, suggesting magma storage in many weakly connected volumes. Future estimates of (an)isotropic seismic velocities and melt fractions across 3D reservoirs may be improved through expanded applications of full waveform tomography to body and surface waves and increasingly dense array studies facilitated by combinations of broadband and rapidly-deployable shorter-period seismographs. Advanced seismic imaging offers potential for improved delineation of magma reservoir boundaries and constraints on intra-reservoir structures such as sill complexes that provide insight into magma reservoir mechanics and compositional heterogeneity.

Author : Ellen Prager
Publisher : University of Chicago Press
Page : 247 pages
File Size : 28,18 MB
Release : 2020-03-02
Category : Science
ISBN : 022654169X

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The Earth is a beautiful and wondrous planet, but also frustratingly complex and, at times, violent: much of what has made it livable can also cause catastrophe. Volcanic eruptions create land and produce fertile, nutrient-rich soil, but they can also bury forests, fields, and entire towns under ash, mud, lava, and debris. The very forces that create and recycle Earth’s crust also spawn destructive earthquakes and tsunamis. Water and wind bring and spread life, but in hurricanes they can leave devastation in their wake. And while it is the planet’s warmth that enables life to thrive, rapidly increasing temperatures are causing sea levels to rise and weather events to become more extreme. Today, we know more than ever before about the powerful forces that can cause catastrophe, but significant questions remain. Why can’t we better predict some natural disasters? What do scientists know about them already? What do they wish they knew? In Dangerous Earth, marine scientist and science communicator Ellen Prager explores the science of investigating volcanoes, earthquakes, tsunamis, hurricanes, landslides, rip currents, and—maybe the most perilous hazard of all—climate change. Each chapter considers a specific hazard, begins with a game-changing historical event (like the 1980 eruption of Mt. St. Helens or the landfall and impacts of Hurricane Harvey), and highlights what remains unknown about these dynamic phenomena. Along the way, we hear from scientists trying to read Earth’s warning signs, pass its messages along to the rest of us, and prevent catastrophic loss. A sweeping tour of some of the most awesome forces on our planet—many tragic, yet nonetheless awe-inspiring—Dangerous Earth is an illuminating journey through the undiscovered, unresolved, and in some cases unimagined mysteries that continue to frustrate and fascinate the world’s leading scientists: the “wish-we-knews” that ignite both our curiosity and global change.

Author : Tim Burt
Publisher : Cambridge University Press
Page : 415 pages
File Size : 38,51 MB
Release : 2020-02-20
Category : Education
ISBN : 1108428045

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Proclaims the enjoyment of teaching, studying and learning outdoors via the inspirational stories of some remarkable people.

Author : National Academies of Sciences, Engineering, and Medicine
Publisher : National Academies Press
Page : 135 pages
File Size : 44,79 MB
Release : 2017-07-24
Category : Science
ISBN : 0309454158

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Volcanic eruptions are common, with more than 50 volcanic eruptions in the United States alone in the past 31 years. These eruptions can have devastating economic and social consequences, even at great distances from the volcano. Fortunately many eruptions are preceded by unrest that can be detected using ground, airborne, and spaceborne instruments. Data from these instruments, combined with basic understanding of how volcanoes work, form the basis for forecasting eruptionsâ€"where, when, how big, how long, and the consequences. Accurate forecasts of the likelihood and magnitude of an eruption in a specified timeframe are rooted in a scientific understanding of the processes that govern the storage, ascent, and eruption of magma. Yet our understanding of volcanic systems is incomplete and biased by the limited number of volcanoes and eruption styles observed with advanced instrumentation. Volcanic Eruptions and Their Repose, Unrest, Precursors, and Timing identifies key science questions, research and observation priorities, and approaches for building a volcano science community capable of tackling them. This report presents goals for making major advances in volcano science.

Author : Cathina L. Gunn De Rosas
Publisher :
Page : 153 pages
File Size : 20,84 MB
Release : 2015
Category : Heat equation
ISBN :

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Understanding the genesis, incubation, evolution and equilibration of silicic magma reservoirs that drive and source volcanic activity all over the planet is fundamental to the discipline of geology. The subsurface processes of magma infiltration, transport, alteration and fractionation determine the volumetric rate of crustal production as well as its chemical composition, pluton and batholith formation, the chemical and thermal evolution of the crust and the severity and frequency of volcanic extrusion, flood basalts and ocean ridge volcanism. The excess pressure of the magma system, as it evolves and drives surficial eruption, is a key factor in hazard prediction and mitigation for volcanologists all over the world and has the capacity to save human life and property. I develop numerical models that explore the temporal and spatial evolution of magmatic systems. In chapter 2, I explore the thermodynamics of a developing magma reservoir in the Earth. I experiment with varying sill thicknesses and emplacement rates of magma into the shallow crust using a multi-physics FEM solver and discuss the most efficient rates of emplacement as well as the significant sill thickness plays in the resultant reservoir volume (magma retaining a temperature > 1150 K) as a function of time. I also explore sensitivity of the model to various thermodynamic parameters in the magma and the crust; namely, thermal conductivity, specific heat capacity and the injection temperature of the magma. I find that sill thickness, contrary to previous work, plays a significant role in the volume of magma reservoirs emplaced at any given geologic rate. In chapter 3, I implement mechanical heterogeneity around a mature magma reservoir to discuss the implications such a zone of modified, heated, crust has on source pressure values in a swelling magma chamber. Previous work at other volcanic centers has shown that treating the crust as a purely elastic medium where large magma reservoirs are concerned (such as at Mt. Etna, Campi Flegrei and the Taal Volcano) inflates the pressure estimates for long-term inflation magnitudes by as much as 400%. I use a multiphysics solver to model fluid flow into a shallow chamber and the resultant mechanical deformation of the surrounding crust with and without the modified elasto-plastic zone inferred, and discuss pressure source values for both. I also discuss differences in the uniform pressure distribution of deformation modeled in previous studies at Soufrière Hills Volcano and my magmastatic model. In chapter 4, I explore the dynamics of ascending magma in the feeder-dike system at Soufrière Hills Volcano and develop a method that attempts to track potential inflation of the system and invert real-time geodetic measurements of surface displacements to volumetrically quantify short-term perturbations in the subsurface of an active volcano. I show that volumetric inflation of the surface can be directly related to pressures in the dike-system, magma flow rates and volatile contents within useful ranges and discuss next steps to create a viable end-product.

Author : Francesca Cigna
Publisher : MDPI
Page : 430 pages
File Size : 33,54 MB
Release : 2021-03-17
Category : Science
ISBN : 3036501266

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Remote sensing data and methods are increasingly being implemented in assessments of volcanic processes and risk. This happens thanks to their capability to provide a spectrum of observation and measurement opportunities to accurately sense the dynamics, magnitude, frequency, and impacts of volcanic activity. This book includes research papers on the use of satellite, aerial, and ground-based remote sensing to detect thermal features and anomalies, investigate lava and pyroclastic flows, predict the flow path of lahars, measure gas emissions and plumes, and estimate ground deformation. The multi-disciplinary character of the approaches employed for volcano monitoring and the combination of a variety of sensor types, platforms, and methods that come out from the papers testify to the current scientific and technology trends toward multi-data and multi-sensor monitoring solutions. The added value of the papers lies in the demonstration of how remote sensing can improve our knowledge of volcanoes that pose a threat to local communities; back-analysis and critical revision of recent volcanic eruptions and unrest periods; and improvement of modeling and prediction methods. Therefore, the selected case studies also demonstrate the societal impact that this scientific discipline can potentially have on volcanic hazard and risk management.

Author : Heidy M. Mader
Publisher : Geological Society of London
Page : 304 pages
File Size : 18,63 MB
Release : 2006
Category : Nature
ISBN : 9781862392083

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Statistics in Volcanology is a comprehensive guide to modern statistical methods applied in volcanology written by today's leading authorities. The volume aims to show how the statistical analysis of complex volcanological data sets, including time series, and numerical models of volcanic processes can improve our ability to forecast volcanic eruptions. Specific topics include the use of expert elicitation and Bayesian methods in eruption forecasting, statistical models of temporal and spatial patterns of volcanic activity, analysis of time series in volcano seismology, probabilistic hazard assessment, and assessment of numerical models using robust statistical methods. Also provided are comprehensive overviews of volcanic phenomena, and a full glossary of both volcanological and statistical terms. Statistics in Volcanology is essential reading for advanced undergraduates, graduate students, and research scientists interested in this multidisciplinary field.