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- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
The impact of natural disasters has become an important and ever-growing preoccupation for modern societies. Volcanic eruptions are particularly feared due to their devastating local, regional or global effects. Relevant scientific expertise that aims to evaluate the hazards of volcanic activity and monitor and predict eruptions has progressively developed since the start of the 20th century. The further development of fundamental knowledge and technological advances over this period have allowed scientific capabilities in this field to evolve. Hazards and Monitoring of Volcanic Activity groups a number of available techniques and approaches to render them easily accessible to teachers, researchers and students. This volume reviews the different monitoring methods. It first considers fluids and solid products, approaches that provide valuable information on pre-eruptive processes and eruption dynamics. It also focuses on the description of geophysical monitoring methods under development.
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Seitenzahl: 427
Veröffentlichungsjahr: 2022
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Table of Contents
Cover
Title Page
Copyright
Foreword
Preface
List of Abbreviations
1 Monitoring of Volcanic Fluids
1.1. Introduction
1.2. Composition, solubility and exsolution of magmatic gases
1.3. In situ sampling and analysis techniques for volcanic fluids
1.4. Contribution of melt inclusions to geochemical monitoring
1.5. Example of monitoring
1.6. Recommendations for fluid monitoring
1.7. References
2 Monitoring of Eruptive Products: Deposits Associated with Pyroclastic Fallout
2.1. Introduction
2.2. General characteristics of pyroclastic fallout deposits
2.3. Importance of the scale of analysis (from whole deposit to particles)
2.4. Sampling and syn- and post-eruptive parameters
2.5. Pyroclastic scale measurements
2.6. Petrographic and geochemical analysis of pyroclastic products
2.7. Measurements at the scale of pyroclastic deposits
2.8. Total grain size distribution
2.9. Plume heights
2.10. Mass discharge rate
2.11. Temperature
2.12. Ballistic parameters
2.13. References
3 Monitoring of Eruptive Products: Pyroclastic Density Currents and Their Deposits
3.1. Introduction
3.2. General characteristics of pyroclastic density currents and their deposits
3.3. The importance of scale in the joint study of deposition and individual particles
3.4. Syn-eruptive and post-eruptive measurements
3.5. Perspectives
3.6. References
4 Gravity Monitoring of Volcanoes
4.1. Introduction
4.2. Instruments
4.3. Measurement procedures
4.4. External phenomena generating temporal variations of gravity
4.5. Causes of gravimetric variations on volcanoes
4.6. Case studies
4.7. Study and monitoring by muography
4.8. Perspectives
4.9. Acknowledgment
4.10. References
5 Electrical and Electromagnetic Monitoring of Volcanoes
5.1. Introduction
5.2. Phenomena at the origin of resistivity and electric or EM field variations
5.3. Natural and induced electric and EM fields
5.4. Monitoring: instruments and procedures
5.5. Perspectives
5.6. Acknowledgment
5.7. References
6 Magnetic Monitoring of Volcanoes
6.1. Introduction
6.2. Phenomena generating magnetization and magnetic field variations
6.3. Monitoring: instruments and procedures
6.4. Case studies
6.5. Perspectives
6.6. Acknowledgment
6.7. References
List of Authors
Index
End User License Agreement
List of Tables
Chapter 2
Table 2.1. Important parameters of pyroclastic fallout for hazard assessment
Table 2.2. List of the main particle size parameters
Table 2.3. Main long-lived decay systems used as tracers
Table 2.4. Descriptive table of the tools shown in Figure 2.36
Table 2.5. Temperature measured in pyroclastic flow deposits and from natural or...
Chapter 3
Table 3.1. List of abbreviations describing the PDC lithofacies used in this cha...
Table 3.2. Key PDC depositional parameters relevant to hazard assessment
List of Illustrations
Chapter 1
Figure 1.1. a) Variability in the chemical composition of volcanic fluids (fumar...
Figure 1.2. Diagram summarizing the different types of volcanic fluids in a magm...
Figure 1.3. Example of gas sampling and composition at Soufrière, Guadeloupe. a)...
Figure 1.4. a) Temporal evolution of the CO2/SO2 ratio of the Stromboli volcanic...
Figure 1.5. a) Gas concentrations are measured with a MultiGas at different heig...
Figure 1.6. Sampling of the dilute volcanic plume from Lascar volcano, Chile, by...
Figure 1.7. Daily averages of CO2 fluxes from the ground, as well as daily seism...
Figure 1.8. Method for measuring soil CO2 fluxes. a) Direct method: a hermetic b...
Figure 1.9. Time series of Cl (ppm), Br (*300), I (*3*104) and Cl/Br composition...
Figure 1.10. 3He/4He Ra (R/Ra) versus 4He/20Ne measured in hot springs from Copa...
Figure 1.11. Variations in 3He/4He (Ra) and δ13C–CO2 over time in thermal waters...
Figure 1.12. a) Example of Sakurajima (Kyushu, Japan) with direct hot spring sam...
Figure 1.13. Melt inclusion, with its thermal retraction bubble, trapped in an o...
Figure 1.14. Time series of Poas volcano monitoring from 2013 to 2018. For a col...
Chapter 2
Figure 2.1. a) Primary volcanic plume from the Plinian eruption of Pinatubo in 1...
Figure 2.2. a) Juveniile and non-juuvenile pyrocllasts from thee fallout depoosi...
Figure 2.3. Isopach maps of pyroclastic fallout deposits from different eruption...
Figure 2.4. Different sampling strategies. For a color version of this figure, s...
Figure 2.5. Example of a list of information useful for describing the eruption ...
Figure 2.6. Classification of volcanic products based on size and shape of pyroc...
Figure 2.7. a) Real-time data verification as ash falls within the ASHER light b...
Figure 2.8. Density and size of bombs and slag from an explosion at Stromboli. F...
Figure 2.9. Temporal sequence of a strombolian explosion during the July 2015 er...
Figure 2.10. Classical particle size analysis of a pyroclastic deposit
Figure 2.11. a) Simplified schematic of the Malvern Mastersizer 3000 particle si...
Figure 2.12. a) View of the Stromboli active area (June 2008) showing the sampli...
Figure 2.13. a) Locations of the identified and sized bombs on the summit area o...
Figure 2.14. a) Stratigraphic log of fallout deposits from the sub-Plinian basal...
Figure 2.15. Lithological counting (or component analysis). Images of different ...
Figure 2.16. Different pyroclastic components identified within the deposits of ...
Figure 2.17. Lithological counting from images of the deposits. For a color vers...
Figure 2.18. a) Histogram of the particle size distribution of an ash sample fro...
Figure 2.19. When a large number of modal analyses are required, as many points ...
Figure 2.20. Strombolian explosions during the July 2015 eruption at Piton de la...
Figure 2.21. Operation of the Malvern Morphologi G3 (modified according to Leibr...
Figure 2.22. Morphological analysis of a series of ash samples from the Septembe...
Figure 2.23. a) Example of how X-ray micro-tomography works. b) Results of imagi...
Figure 2.24. Density measurements
Figure 2.25. a) Densities and porosities of samples from the September 2016 erup...
Figure 2.26. a) Permeability versus porosity of samples from several eruptions o...
Figure 2.27. Textural analysis procedure (vesicles and crystals) on samples such...
Figure 2.28. Textural data from the September 2016 eruption at Piton de la Fourn...
Figure 2.29. Backscatter electron images of common magmatic textures in juvenile...
Figure 2.30. Composition of lavas produced by the submarine eruption (2018–2021)...
Figure 2.31. a) Evolution of MgO content with temperature for glasses in equilib...
Figure 2.32. Backscattered electron images of zoned phenocrysts
Figure 2.33. Backscattered electron image of a reversely zoned olivine crystal f...
Figure 2.34. Profile through the olivine crystal of Figure 2.33 (white line) sho...
Figure 2.35. Relationship between historical eruptive activity of Piton de la Fo...
Figure 2.36. Tools needed to perform field measurements on pyroclastic deposits ...
Figure 2.37. Examples of planimeters: a) polar and b) digital
Figure 2.38. Graphical representation of the volume calculation using the trapez...
Figure 2.39. Example of a graph associated with the May 18, 1980 Mount St. Helen...
Figure 2.40. Example of a graph associated with the May 18, 1980 Mount St. Helen...
Figure 2.41. Examples of different interpolators. a) TIN; b) NNI; c) IDW and d) ...
Figure 2.42. Methods of calculating the TGSD. For a color version of this figure...
Figure 2.43. Sketch showing the main characteristics of a) a strong volcanic plu...
Figure 2.44. Schematic representation of the influence of a crosswind on the dep...
Figure 2.45. a) Crosswind range versus maximum tailwind range for different clas...
Figure 2.46. a) Example of sampling a section of a specific area, where the dept...
Figure 2.47. Variation of eruptive spout heights (Hb and Ht, see Figure 2.42) wi...
Figure 2.48. a) Plume height versus log of deposit mass associated with Plinian ...
Figure 2.49. Plume height above blowhole versus mass discharge rate for eruption...
Figure 2.50. a) Roman amphorae from the archeological site of Pompeii, covered b...
Figure 2.51. Isopleth map of ballistic fallout from the proximal area of Ruapehu...
Figure 2.52. a) Schematic diagram showing two probable areas of ballistic projec...
Figure 2.53. a) and b) Strombolian ballistic bombs of mafic compositions origina...
Chapter 3
Figure 3.1. Two examples of pyroclastic density currents (PDC): a) the August 7,...
Figure 3.2. Non-genetic classification scheme for primary tephra (modified from ...
Figure 3.3. Examples of pyroclasts, lithofacies and deposits associated with PDC...
Figure 3.4. Flow direction (anisotropic magnetic susceptibility, AMS) and temper...
Figure 3.5. Methodology for PDC tracking from the temperature of the outer envel...
Figure 3.6. Methodology for tracing a PDC from infrasound measurements. For a co...
Figure 3.7. a) Classification of clast shapes, examples of clast imbrications fr...
Figure 3.8. a) Susceptibility ellipsoid (modified according to Cañón-Tapia and M...
Figure 3.9. a) Maximum runout defined by the Voronoi tessellation. b) Maximum pr...
Figure 3.10. Concentration profiles of a) a turbulent, fully diluted current and...
Figure 3.11. Two conceptual vertical velocity profiles in PDCs with a lower dens...
Figure 3.12. Doppler radar data displayed as a velocigram (modified according to...
Figure 3.13. a) Example of erosional furrows from Lascar volcano (modified accor...
Figure 3.14. a) Log (stratigraphic section) and b) photo of coarse-tail grading ...
Figure 3.15. Walls having been knocked down by the most energetic PDCs of the 79...
Figure 3.16. a) Six screenshots associated with the September 10, 2010 PDC at So...
Figure 3.17. Grain behavior during stepwise thermal demagnetization
Figure 3.18. Procedure for determining the Tdep for a PDC deposit. For a color v...
Chapter 4
Figure 4.1. Field measurement with a relative gravimeter. The altitude at the ti...
Figure 4.2. A portable A10 absolute gravity meter measuring on a geodetic benchm...
Figure 4.3. Etna gravity monitoring network (from Greco et al. (2012)). For a co...
Figure 4.4. Example of a microgravity monitoring measurement strategy with a mix...
Figure 4.5. Examples of positive mass changes in a structure
Figure 4.6. Types of mass and density change with changes in gravity and altitud...
Figure 4.7. Mass changes (>0 in red, <0 in blue) in response to the evolution of...
Figure 4.8. Mass changes in response to the evolution of a magmatic system and s...
Figure 4.9. Mass changes in response to volcano-tectonic events. For a color ver...
Figure 4.10. a) Kilauea caldera prior to the 2018 crisis and associated Bouguer ...
Figure 4.11. a) Location of the microgravity reiteration network set up on Piton...
Figure 4.12. a) The Dolomieu before and after its collapse in 2007 (OVPF photos)...
Figure 4.13. a) A 3-plane telescope. Note the orientation devices (from Marteau ...
Figure 4.14. Muon image of La Soufrière of Guadeloupe (from Lesparre et al. (201...
Figure 4.15. Density variations (normalized to the highest density) integrated o...
Chapter 5
Figure 5.1. Illustration of the electrolytic conduction of a rock
Figure 5.2. Expected low-pressure resistivity for a fluid-saturated basalt as a ...
Figure 5.3. Illustration of the different phenomena that can cause resistivity v...
Figure 5.4. Illustration of methods for measuring direct current resistivity. Th...
Figure 5.5. Monitoring of the Izu-Oshima volcano with direct current
Figure 5.6. Principles of depth resistivity measurement by active (artificially ...
Figure 5.7. Schematic of the ACTIVE network on Izu-Oshima volcano. From Utada et...
Figure 5.8. Cross-section of a conductivity variation model during 4 years of me...
Figure 5.9. Piton de la Fournaise EM network (1996–1999), in blue, and cracks fr...
Figure 5.10. Evolution of apparent resistivity during the 1998 crisis. Modified ...
Figure 5.11. VLF response (ellipticity and tilt – see text) above a lava flow ci...
Figure 5.12. a) PS monitoring electrode array at Miyakejima before the 2000 cris...
Chapter 6
Figure 6.1. Example of sources of stress variations in volcanoes
Figure 6.2. Piezomagnetic effect for a pressure variation associated with the op...
Figure 6.3. Piezomagnetic effect for a pressure variation of +200 MPa of a spher...
Figure 6.4. Diagram illustrating the dependence of magnetization on temperature
Figure 6.5. Permanent magnetic monitoring network of Etna. A remote station not ...
Figure 6.6. Map of Kilauea Iki and location of magnetic measurements. From Gaill...
Figure 6.7. a) Modeled magnetic anomalies along a nearly W-E profile at the surf...
Figure 6.8. Subcontinuous record of magnetic field variations at a station in Wh...
Figure 6.9. In red: variations of the magnetic field intensity at a station near...
Figure 6.10. Recording of magnetic field variations by stations north of the sum...
Figure 6.11. Magnetic variations (in nT) during the 2000 Miyakejima volcano cris...
Guide
Cover
Table of Contents
Title Page
Copyright
Foreword
Preface
List of Abbreviations
1 Monitoring of Volcanic Fluids
List of Authors
Index
End User License Agreement
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SCIENCES
Geoscience, Field Director – Yves Lagabrielle
Lithosphere–Asthenosphere Interactions, Subject Head – René Maury
Hazards and Monitoring of Volcanic Activity 3
Gravimetric, Electric and Magnetic Fluids, Products and Methods
Coordinated by
Jean-François Lénat
First published 2022 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.
Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address:
ISTE Ltd
27-37 St George’s Road
London SW19 4EU
UK
www.iste.co.uk
John Wiley & Sons, Inc.
111 River Street
Hoboken, NJ 07030
USA
www.wiley.com
© ISTE Ltd 2022
The rights of Jean-François Lénat to be identified as the author of this work have been asserted by him in accordance with the Copyright, Designs and Patents Act 1988.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s), contributor(s) or editor(s) and do not necessarily reflect the views of ISTE Group.
Library of Congress Control Number: 2022938792
British Library Cataloguing-in-Publication Data
A CIP record for this book is available from the British Library
ISBN 978-1-78945-046-0
ERC code:
PE10 Earth System Science
PE10_5 Geology, tectonics, volcanology
PE10_7 Physics of earth’s interior, seismology, volcanology
Foreword
Claude JAUPART
Institut de physique du globe de Paris, Université de Paris, Académie des sciences, Paris, France
Volcanoes are fascinating because of the beautiful landscapes they form and their superb eruptions. Many books have documented the most catastrophic eruptions, the different eruptive regimes and the physical mechanisms involved. Others have popularized tales of adventurers getting close to volcanic explosions and flows at the risk of their lives. In comparison, the discreet and dedicated work of volcanologists monitoring volcanoes has remained little known. The methods and techniques they use have improved greatly in recent decades and now allow them to predict eruptions with very few limitations. These advances are to be presented and explained in the three volumes of this book.
Volcanoes are built on top of a vast network of underground plumbing, and it is within this network that eruptions occur. Near the surface, the permeable rocks are gorged with water that circulates, heats up at depth and vaporizes under widely varying conditions. The result is a myriad of manifestations, including fumarole fields with changing flows, small earthquakes and ground deformation. This high background noise makes monitoring difficult. An eruption is preceded by the setting in motion of magma from one or more reservoirs located several kilometers underground. This onset is often very discrete and the associated signals are not easily distinguished from the background noise. Once the magma is near the surface, the signs are numerous and leave no room for doubt, but things can move very quickly and it is often too late to evacuate the area. Simply recognizing that an eruption is imminent is not enough: one must also assess its intensity and regime. Sometimes an eruption can even occur without magma and take the form of phreatic explosions, where the water contained in the surface rocks of the volcano vaporizes explosively. The volcanologist’s work does not stop when the eruption begins; they must follow it over time and be able to distinguish between a temporary stop and its true end.
Faced with these multiple challenges, volcanologists have adopted methods that can be divided into two broad categories. The first is the historical study that reconstructs the past eruptions of a volcano and the time intervals between them. Knowing that an eruption covers the deposits of those that preceded it and destroys most of them, establishing a reliable chronology and estimating the volumes ejected rely on particular sampling strategies and frequent round trips between the field and the laboratory. New dating methods had to be developed to determine the ages of deposits older than a few tens of thousands of years. The second category covers all the physical and chemical methods used to determine the deep structure of a volcano and to locate the perturbations that it hosts. Rocks are difficult to penetrate and do not allow us to observe the reservoirs and conduits that feed eruptions. The information we obtain is indirect and often ambiguous. For example, small earthquakes are recorded, but they can be caused by the opening of cracks in a hydrothermal system or by magma that moves or by isolated landslides in places that are not easily accessible. An area of abnormal electrical conductivity can be detected, but it may be weathered rock or rock with water-filled fractures. Volcanologists have improved the uncertainty by combining several methods and have added to their toolbox over the years.
Remarkable progress has been made in the last four decades. Previously, the equipment available was limited to a few heavy and unwieldy devices designed for larger scale studies. Measurements have become much more precise, the number of sensors has increased enormously and the mathematical techniques of analysis have been refined. Well-instrumented observatories have been installed on many active volcanoes and in particular on the three volcanoes of the French national territory in Guadeloupe, Martinique and Reunion Island. Nowadays, a “typical” observatory maintains more than a hundred sensors of all kinds. The last two decades have seen the advent of very efficient satellite tools. However, it should not be inferred that volcanology has become the business of pure measurement experts or laboratory researchers. Knowledge of the special features of each volcano is needed to advance. The active volcano of Santorini in the Cyclades, which grows in the middle of a large caldera, is not monitored in the same way as Piton de la Fournaise on Reunion Island, which rises nearly 7 km above the sea floor and grows on the flanks of the ancient Piton des Neiges. It would be absurd to sample the deposits and install sensors randomly or only in easily accessible locations. Every volcanologist, whether geologist, geophysicist or geochemist, has studied their volcanoes for several years. This patient work has rarely been described. In this book, specialists from all the major disciplines of volcanology share their work and their discoveries. They explain how they decipher and interpret their measurements. One is likely to be surprised by the weakness of the signals detected, which can only be measured with sophisticated instruments, in comparison with the enormity of the eruptive phenomena. But it is thanks to these signals that we are able to travel to the very heart of volcanoes.
Preface
Jean-François LÉNAT
Laboratoire Magmas et Volcans, CNRS, IRD, OPGC, Université Clermont Auvergne, Clermont-Ferrand, France
The impact of natural disasters has become a major concern of our modern societies. Volcanic eruptions, although statistically less deadly and causing less damage than earthquakes or certain atmospheric phenomena, can have devastating local or global effects.
The methods used to determine hazards related to volcanic activity and to monitor the latter are part of many Earth science curricula, both at master and thesis levels.
There are many publications in these areas, but the information is fragmented, requiring teachers to consult a large number of documents to develop their teaching. The aim of this book is to provide them with a single resource, written by specialists, on the methods of monitoring and determining hazards.
The subject is vast, which has led us to present it in three volumes. The first is devoted to geological and historical approaches. The next two are devoted to monitoring methods. The aim of each chapter is not to be encyclopedic. Rather, the intention is to provide the reader with the basic fundamentals of each of the topics covered. On the other hand, each author has taken care to provide bibliographic references that will allow readers to find the detailed information they may need.
This book deals with a scientific field that is constantly evolving. The progress in scientific concepts, approaches, observations and techniques has been spectacular during the last decades. There is no reason why this dynamic should slow down in the future. A logical consequence is that updates should be made periodically to avoid obsolescence of such a book. We therefore hope that it will be useful in the present period and that future editions will enable it to retain its value over time.
March 2022
List of Abbreviations
ACTIVE
Array of Controlled Transient-electromagnetics for Imaging a Volcanic Edifice
AMS
Anisotropic Magnetic Susceptibility
AMT
Audio-magnetotelluric
ASHER
Disdrometer dedicated to the detection of ash
CSD
Crystal Size Distribution
DOAS
Differential Optical Absorption Spectroscopy
FDEM
Frequency Domain Electromagnetics
FOAMS
Fast Objects Analysis and Measurement System
FTIR
Fourier Transform Infrared Spectroscopy
LOTEM
Long Offset Transient Electromagnetics
MC-ICPMS
Plasma source mass spectrometer
MDR
Mass Discharge Rate
MEMS
Microelectromechanical systems
MT
Magnetotelluric
MultiGas
MultiGas analysis system
PDC
Pyroclastic Density Currents
PSD
Particle Size Distribution
SEM
Scanning Electron Microscopy
SP
Spontaneous Polarization
TDEM
Time Domain Electromagnetic
TFV
Terminal Fall Velocity
TGSD
Total Grain Size Distribution
TIMS
Solid source mass spectrometer
VEI
Volcanic Explosivity Index
VLF
Very Low Frequency
VSD
Vesicle Size Distribution
