Download or read book Changing Eruption Dynamics Associated with Caldera Collapse written by Anna Paula Vinkler and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stress Field Control of Eruption Dynamics written by Roberto Sulpizio and published by Frontiers Media SA. This book was released on 2017-10-10 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing evidence supports the claim that stress changes play a fundamental role in triggering volcanic eruptions. Stress changes may vary in origin to include earthquakes, erosion and landslide processes, deglaciation, or tidal effects. The local stress can also change as response of magma influx from deeper reservoirs and an increase of the magma/gas pressure. The stress transfer may be of great importance in reawakening a dormant system. As an example, significant statistical correlation of large earthquakes and eruptions in time and space was suggested in many works. The interaction may be two-fold; where magma intrusions may change the stress at active faults and trigger earthquakes, while tectonic earthquakes may affect the magmatic system and change the eruption activity. The change in local tectonic stress has been claimed as trigger of large ignimbrite eruptions or for controlling the eruptive style of explosive eruptions. Sometimes volcano systems that are nested or closely located may become active in chorus; neighbouring volcanoes may interact in the sense that one volcano triggers its neighbouring volcano. However, although there is ample evidence of concurrence, the processes of interacting volcanoes and near- to far-field tectonic stress are not well understood. Some studies suggest that volcanic eruptions are triggered if compressive stress acts at the magma system and “squeezes” out magma. Other studies suggest that extensional stress fields facilitate magma rise and thus encourage eruptions, or that fluctuating compression and extension during the passing of seismic waves trigger eruptions. This research topic tries to address some of the important open questions in interaction between stress field and volcanic eruption, though both review papers and new contributions.
Download or read book Volcanic Eruptions and Their Repose Unrest Precursors and Timing written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2017-07-24 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Volcanotectonics written by Agust Gudmundsson and published by Cambridge University Press. This book was released on 2020-04-30 with total page 601 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explains and illustrates volcanic structures, products and processes, with worked examples and exercises, for students and professionals.
Download or read book Recharge Decompression and Collapse written by Benjamin James Andrews and published by . This book was released on 2009 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-linear volcanic and magmatic processes control the occurrence and behavior of volcanic eruptions. Consequently, understanding the responses of volcanic systems to processes of different length scales, timescales, and magnitudes is critical to interpreting ancient deposits, understanding current eruption dynamics, and predicting future activity. Here I present the results of three studies wherein analytical geochemistry, experimental petrology, and turbulent flow analysis describe otherwise obscured volcanic processes. Injections of new magma are common events in magma chambers. Recharging magma can change the chamber composition and temperature and may facilitate assimilation of country rock. Plagioclase phenocrysts provide an opportunity to examine recharge and assimilation processes, because their compositions are sensitive to temperature and their Sr isotopic ratios can record compositional variations in the chamber. Chemical and isotopic microanalyses of crystals from 7 eruptions of El Chichón Volcano, Mexico, reveal that recharge and assimilation events are very common and mixing is efficient, but individual events seldom affect the entire chamber. During every eruption, magma decompresses and ascends through a conduit from a chamber at depth to a vent at the surface. Changes in pumice textures during the 1800 14C yr BP eruption of Ksudach Volcano, Kamchatka, suggest that conduit structure changed following caldera collapse. Decompression experiments show that the post-collapse pumice decompressed at ~0.0025 MPa/s, compared to pre-collapse decompression rates of >0.01 MPa/s. By balancing those results with eruptive mass fluxes I quantify the effects of caldera collapse on a conduit, and show that collapse resulted in a conduit with a very broad base and narrow vent. Turbulent air entrainment controls whether an eruption column rises buoyantly or collapses to generate pyroclastic flows. Through extensive re-evaluation of video and photographs of the 18 May 1980 eruption of Mount St. Helens, I report the first measurements of the turbulent velocity field of a volcanic column and show that changes in its turbulence reflect changes in eruption behavior. Those results indicate collapse was caused by a reduction in eddy size and turbulent air entrainment initiated by an increased vent size and the development of a buoyant annulus surrounding a dense, collapsing core.
Download or read book Modeling Volcanic Processes written by Sarah A. Fagents and published by Cambridge University Press. This book was released on 2021-02-11 with total page 902 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the physical behavior of volcanoes is key to mitigating the hazards active volcanoes pose to the ever-increasing populations living nearby. The processes involved in volcanic eruptions are driven by a series of interlinked physical phenomena, and to fully understand these, volcanologists must employ various physics subdisciplines. This book provides the first advanced-level, one-stop resource examining the physics of volcanic behavior and reviewing the state-of-the-art in modeling volcanic processes. Each chapter begins by explaining simple modeling formulations and progresses to present cutting-edge research illustrated by case studies. Individual chapters cover subsurface magmatic processes through to eruption in various environments and conclude with the application of modeling to understanding the other volcanic planets of our Solar System. Providing an accessible and practical text for graduate students of physical volcanology, this book is also an important resource for researchers and professionals in the fields of volcanology, geophysics, geochemistry, petrology and natural hazards.
Download or read book The Eruption Dynamics of an Explosive Caldera forming Event written by Adele N. Bear and published by . This book was released on 2008 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Tufo Rosso a Scorie (Sutri E5) exhibits pervasive, homgenous alteration of high alkali tephriphonolitic and phonolitic glass to zeolite minerals (chabazite and phillipsite) in all regions of the study area and at all stratigraphic levels, with the exception of the basal 1m. We infer that a large geothermal field on the surface was destroyed during the closing stages of the Sutri eruption. Incorporation of superheated geothermal fluids, and subsequent entrapment into the pyroclastic flow during eruption column collapse would have greatly reduced emplacement temperature and provided the necessary water needed for post-emplacement zeolitisation, in the absence of phreatomagmatic activity. The Tufo Rosso a Scorie Nere (Sutri E5) is honeycombed with literally hundreds of Etruscan tombs (6th to 3rd century BC). Geotechnical studies on the mechanical properties of zeolitised ignimbrites reveal that the alteration of volcanic glass to zeolite reduces the overall porosity of a deposit, subsequently increasing the uniaxial compressive strength and cohesiveness of the rock framework. The enhanced lithification properties gained by the formation of zeolites, which act like a cementing agent, imply that physically the ignimbrite would have still been a relatively soft rock and suitable for the carving of tombs. However the increased strength and cohesiveness provided by the zeolite framework enhanced the preservation potential of these tombs over time. This study has redefined the internal subdivision of the Sutri Formation, has led to a reconstruction of the evolution of the Sutri eruption. It has provided new insights into the diverse range of virtually contemporaneous eruptive behaviour displayed by phonolitic magma systems and how these variations affect the evolution of caldera collapse. It has also shown that phonolitic caldera systems can generate a variety of juvenile clast types simultaneously that are usually associated with different eruption styles and eruption intensities (i.e. spatter formed by low explosivity fire fountaining to moderately explosive Strombolian activity and pumice formed by highly explosive Plinian style activity). This study has broadened our understanding of the volcanological constraints on the zeolitisation of ignimbrites produced purely magmatic eruptions (no magma-water interaction). It has also provided insight into the enhanced strength and cohesiveness displayed by zeolitised ignimbrites and has considered the geoarchaeological implications of this for Etruscan tomb construction and burial architecture in the Vico region.
Download or read book Dynamics of the 240 A D Caldera forming Eruption of Ksudach Volcano Kamchatka Russia written by Benjamin James Andrews and published by . This book was released on 2004 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The Ksudach Volcano KS-1 rhyodacite deposits offer an opportunity to study eruption dynamics and plume stability during a caldera-forming eruption. Stratigraphic relations indicate four phases of eruption, Initial, Main, Lithic, and Gray. Well-sorted, reverse-graded pumice fall deposits overlying a silty ash compose the Initial phase layers. The Main, Lithic and Gray phases are represented by pumice fall layers interbedded with pyroclastic flow and surge deposits (proximally) and co-ignimbrite ashes (distally). Although most of the deposit is 30 wt.% lithics, the Lithic phase layers are50wt.% lithics. White and gray pumices are compositionally indistinguishable, however vesicle textures and microlite populations indicate faster ascent by the white pumices prior to the Gray phase. The eruption volume is estimated as 7.5 km3 magma (dense rock equivalent) and 2.4 km3 lithics. Isopleth maps indicate mass discharge rates (MDR) ranged from 5-10x107 kg/s in the Initial phase to> 108 kg/s in the Main, Lithic, and Gray phases. Stratigraphic, granulometric, and component analyses indicate simultaneous eruption of buoyant plumes and non-buoyant flows during the Main, Lithic and Gray phases. Caldera collapse during the Lithic phase is reflected by a large increase in lithic particles and the textural change from white to gray pumices; collapse occurred after eruption of 2/3 of the magma"--Leaf iii.
Download or read book Volcanic Unrest written by Joachim Gottsmann and published by Springer. This book was released on 2018-12-18 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book summarizes the findings of the VUELCO project, a multi-disciplinary and cross-boundary research funded by the European Commission's 7th framework program. It comprises four broad topics: 1. The global significance of volcanic unrest 2. Geophysical and geochemical fingerprints of unrest and precursory activity 3. Magma dynamics leading to unrest phenomena 4. Bridging the gap between science and decision-making Volcanic unrest is a complex multi-hazard phenomenon. The fact that unrest may, or may not lead to an imminent eruption contributes significant uncertainty to short-term volcanic hazard and risk assessment. Although it is reasonable to assume that all eruptions are associated with precursory activity of some sort, the understanding of the causative links between subsurface processes, resulting unrest signals and imminent eruption is incomplete. When a volcano evolves from dormancy into a phase of unrest, important scientific, political and social questions need to be addressed. This book is aimed at graduate students, researchers of volcanic phenomena, professionals in volcanic hazard and risk assessment, observatory personnel, as well as emergency managers who wish to learn about the complex nature of volcanic unrest and how to utilize new findings to deal with unrest phenomena at scientific and emergency managing levels. This book is open access under a CC BY license.
Download or read book Understanding Large Caldera In filling Processes written by Madelaine Ann Welcome Willcock and published by . This book was released on 2013 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: The eruption of the Permian Ora caldera of northern Italy during the Hercynian-Variscan tectonic cycle, represents one of the largest explosive eruptions on Earth, having erupted more than 1290 km3 of material, and provides significant information on caldera eruption processes. Research on large caldera volcanoes (> 100 km3) is important due to their potentially devastating global impacts on the natural world and human society. The absence of such an eruption in recent recorded history means fundamental questions remain unanswered regarding the processes related to these volcanoes. The Permian Ora caldera offers a unique opportunity to examine the eruptions of these gigantic systems because of the rare and exceptional preservation and exposure of the intra-caldera fill sequence. The purpose of this study is to document the lithofacies, and the stratigraphic architecture of the Ora caldera, and also to interpret processes such as the timing and nature of caldera collapse, eruption styles, pyroclastic flow processes within the intra-caldera and proximal extra-caldera settings, and caldera in-filling processes. The research approach adopted in this study included detailed field stratigraphic logging, petrographic analysis of componentry and texture, anisotropy of magnetic susceptibility analysis (AMS) of pyroclastic flow patterns, and geochemical analysis. This study has established that the Ora Formation consists of rhyolitic ignimbrite deposits (67.95% - 77.73% SiO2), with sub-ordinate basal volcanic lithic breccia and local interbedded surge layers. The ignimbrite succession is crystal-rich (~25 - 57%; Ø43%), lithic-poor (0 - 46%; Ø2%), has common juvenile clasts (0 to ~45%; Ø20%), is ubiquitously welded, and has a relatively uniform main mineral population (volcanic quartz, sanidine, plagioclase, and biotite). The Ora Formation has been divided into four members (ORAa - ORAd) which consist of (a) a basal volcanic lithic breccia; (b) lithic-rich ignimbrite with minor surge lithofacies; (c) the dominant, thick(> 1 km thickness in total), coarse-crystal-rich ignimbrite (including the bimodal crystal sub-facies), with local interbedded vitrophyre, fine-crystal-rich, and lithic-rich ignimbrite, and minor surge lithofacies deposits; and (d) the fine-crystal-rich ignimbrite with minor lithic-rich ignimbrite lithofacies deposits. These members largely define the eruption phases, from vent opening (member a), vent clearing (member b), waxing and steady eruption (member c), to waning eruption stages (member d). Members a and b reveal caldera collapse occurred from the onset of eruption and identify potential source vent locations, whereas member c illustrates late stage overspill of material from the caldera system. The Ora caldera is proposed as being a volcano-tectonic system, which formed two pene-contemporaneous, coalesced caldera collapse depressions: Northern and Southern. This is interpreted to have occurred via rapid, relatively passive, piston style collapse events, producing a caldera complex approximately 42 x 40 km in size. The ignimbrite succession has a restricted compositional range. Nevertheless, detailed textural, compositional, mineralogical, and stratigraphic data support an eruption evolving from south to north, and the existence of a weakly zoned magma chamber. This is illustrated particularly by a subtle northwards decrease in modal free crystal biotite abundance across the deposit. Other major findings based on fieldwork and laboratory studies include: (i) the absence of a Plinian fallout deposit, indicating that a buoyant Plinian eruption column did not form; (ii) the eruption was marked by a low, continuously collapsing eruption fountain style, which was limited from the outset by catastrophic caldera collapse and decompression of the magma chamber; (iii) the vent was a fissure system with multiple discharge points, feeding more or less on-going, subtly different, pyroclastic flow pulses; (iv) the vertical lithofacies changes record temporal variation in eruption intensity, source material, and source location, demonstrating an incremental caldera in-filling process; (v) the AMS magnetic fabric of the ignimbrite succession indicates changing vertical and lateral pyroclastic flow directions and source locations of the flow pulses; (vi) the pyroclastic flow system was a hot and poorly expanded, high particle concentration, granular density current, with laminar shear forces close to the depositional boundary, and limited ash winnowing; and (vii) the eruption style and pyroclastic flow dynamics facilitated complete deposit welding, illustrated by plastically deformed juvenile shard and fiamme clast morphologies.This research has detailed for the first time the eruptive products and stratigraphy of the Ora Formation and reconstructed the eruption processes and evolution of the Ora caldera system. Key findings include identification of the relative timing of caldera collapse, the caldera in-filling processes, and delineation of a lithostratigraphic and chemical architecture within the deposits. These results highlight the vital role investigation of the intra-caldera deposit plays in understanding of caldera processes. The intra-caldera ignimbrite succession shares many of the general characteristics described for ignimbrites in the extra-caldera setting, which implies that classification schemes and models of pyroclastic flow and emplacement processes are largely transferable between the two settings.
Download or read book Caldera Volcanism written by Joachim Gottsmann and published by Elsevier. This book was released on 2011-09-22 with total page 517 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume aims at providing answers to some puzzling questions concerning the formation and the behavior of collapse calderas by exploring our current understanding of these complex geological processes. Addressed are problems such as:- How do collapse calderas form? - What are the conditions to create fractures and slip along them to initiate caldera collapse and when are these conditions fulfilled? - How do these conditions relate to explosive volcanism?- Most products of large caldera-forming eruptions show evidence for pre-eruptive reheating. Is this a pre-requisite to produce large volume eruptions and large calderas?- What are the time-scales behind caldera processes? - How long does it take magma to reach conditions ripe enough to generate a caldera-forming eruption?- What is the mechanical behavior of magma chamber walls during caldera collapse? Elastic, viscoelastic, or rigid? - Do calderas form by underpressure following a certain level of magma withdrawal from a reservoir, or by magma chamber loading due to deep doming (underplating), or both?- How to interpret unrest signals in active caldera systems?- How can we use information from caldera monitoring to forecast volcanic phenomena?In the form of 14 contributions from various disciplines this book samples the state-of-the-art of caldera studies and identifies still unresolved key issues that need dedicated cross-boundary and multidisciplinary efforts in the years to come. International contributions from leading experts Updates and informs on all the latest developments Highlights hot topic areas and identifies and analyzes unresolved key issues
Download or read book Mechanisms of Activity and Unrest at Large Calderas written by Claudia Troise and published by Geological Society of London. This book was released on 2006 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large caldera collapses represent catastrophic natural events, second only to large meteoritic impacts. In addition, some calderas are densely populated, making the risk extreme, even for moderate eruptions. Understanding caldera mechanisms, unrest and the danger of eruption is therefore a crucial challenge for Earth sciences. Several key features of caldera behaviour have yet to be fully understood. Through a combination of case studies and theoretical modelling, the following topics are addressed in this volume: the conditions required to produce and to release large volumes of magma erupted during caldera formation; how magmatic feeding systems evolve before and after a caldera has formed; the processes that limit the behaviour of precursors to eruptions; how pre-eruptive precursors can be distinguished from those that drive unrest without an eruption; and given that post-collapse eruptions may occur across a wide area, the optimum procedures for designing hazard maps and mitigation strategies.
Download or read book Historical unrest at the large calderas of the world written by Christopher G. Newhall and published by . This book was released on 1988 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Guajara Formation written by Jill Middleton and published by . This book was released on 2006 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hawaiian Volcanoes written by Rebecca Carey and published by John Wiley & Sons. This book was released on 2015-02-20 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hawaiian Volcanoes, From Source to Surface is the outcome of an AGU Chapman Conference held on the Island of Hawai‘i in August 2012. As such, this monograph contains a diversity of research results that highlight the current understanding of how Hawaiian volcanoes work and point out fundamental questions requiring additional exploration. Volume highlights include: Studies that span a range of depths within Earth, from the deep mantle to the atmosphere Methods that cross the disciplines of geochemistry, geology, and geophysics to address issues of fundamental importance to Hawai‘i’s volcanoes Data for use in comparisons with other volcanoes, which can benefit from, and contribute to, a better understanding of Hawai‘i Discussions of the current issues that need to be addressed for a better understanding of Hawaiian volcanism Hawaiian Volcanoes, From Source to Surface will be a valuable resource not only for researchers studying basaltic volcanism and scientists generally interested in volcanoes, but also students beginning their careers in geosciences. This volume will also be of great interest to igneous petrologists, geochemists, and geophysicists.
Download or read book Characteristics of Hawaiian Volcanoes written by Taeko Jane Takahashi and published by Government Printing Office. This book was released on 2014 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: Characteristics of Hawaiian Volcanoes establishes a benchmark for the currrent understanding of volcanism in Hawaii, and the articles herein build upon the elegant and pioneering work of Dutton, Jagger, Steams, and many other USGS and academic scientists. Each chapter synthesizes the lessons learned about a specific aspect of volcanism in Hawaii, based largely o continuous observation of eruptive activity and on systematic research into volcanic and earthquake processes during HVO's first 100 years. NOTE: NO FURTHER DISCOUNTS FOR ALREADY REDUCED SALE ITEMS.
Download or read book Linking subaqueous subglacial and subaerial volcanism How water influences eruption dynamics and creation of volcanic products written by Tobias Dürig and published by Frontiers Media SA. This book was released on 2023-10-25 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
