Introduction

Some of the questions addressed in the course include the following: 

• How do polygenetic volcanoes form and develop their shapes?
• What are the common depths and sizes of magma chambers?
• How do magma chambers form and function and what portion of the magma leaves the chamber in a typical eruption?
• What are the conditions for magma-chamber rupture and dike injection during an unrest period?
• How can we estimate the magmatic pressure in a magma chamber and in a dike?
• How can we forecast the likely paths of injected dikes?
• Why do most injected dikes not reach the surface to supply magma to an eruption?
• What are the mechanical conditions for the formation of collapse calderas?
• What are the mechanical conditions for very large eruptions (super-eruptions)? 

These are all fundamental questions in volcanology and belong to the subfield of volcanology named volcanotectonics. This subfield combines the analysis and use of geological, geophysical, and geochemical data, derived from direct field studies or remotely, with theoretical modelling, derived primarily from the principles of classical physics and its modern developments within the various fields of mechanics.

A magma-filled fracture that propagates from its source to the Earth’s surface initiates a volcanic eruption.  The source of the magma-filled fracture is normally either a shallow magma chamber or a deep-seated reservoir. The magma-filled fracture is either a subvertical dike or an inclined sheet (cone sheet).

One focus of the course is on understanding the conditions that result in magma-chamber/reservoir rupture, dike/sheet injection and propagation, and, eventually, eruption.  Most volcanic unrest periods – periods with increase in various geological, geophysics, and geochemical signals from a volcano – do not result in magma-chamber rupture.  And of those unrest periods that lead to magma-chamber rupture and dike/sheet injection, most do not result in eruptions.  This is because most dike/sheet segments injected from a chamber become arrested – stop their propagation towards the surface – at a certain depth in the crust and therefore never supply magma to an eruption. Explaining the physical conditions that must be satisfied for an injected dike/sheet to reach the surface or, alternatively, become arrested constitutes the foundation of reliable eruption forecasting and, therefore, volcanic hazard assessments.

For a magma chamber to rupture, it must first exist.  Part of the course will be on the conditions for the formation of magma chambers. These are basically of two types, shallow chambers and deep-seated reservoirs.  The shallow chambers are normally with roofs at 6 km or less below the surface, whereas the deep-seated reservoirs are located in the mid-crust or at or close to the crust-mantle boundary.  In the course we show many examples of extinct shallow magma chambers, particularly from Chile and Iceland, and discuss their shapes and sizes in relation to geodetic and seismological data on active shallow magma chambers.

Shallow magma chambers are a necessary condition for the formation of polygenetic (central) volcanoes. In the course we explain that shallow chambers acts as sinks and sources for magma. They act as sinks in the sense that they draw in magma from one or more (normally much larger) deep-seated reservoirs. And the chambers act as sources for dikes, inclined sheets, and, of course, eruptions of the associated volcanoes. The fact that the shallow chamber channels magma to a limited area on the surface is the main reason why polygenetic volcanoes form, rise high above their surroundings, and obtain their common geometries.

During their lifetime, many polygenetic volcanoes collapse once or several times. There are lateral collapses (landslides) and vertical collapses (caldera collapses). In the course the focus is on the latter. Many caldera collapses give rise to eruptions, but some do not. We provide field data and theoretical models to explain the formation of collapse calderas, with examples from volcanoes around the world. Caldera collapses occur much more rarely than dike/sheet injections in a given volcano, so that very special mechanical conditions must be satisfied for a collapse to occur. In the course these conditions are explained and discussed.

While some caldera collapses do not result in eruptions, others give rise to eruptions of various sizes, including some of the largest ones that occur on Earth. In the course field data and theoretical models are provided to explain the mechanics of large eruptions – including those that pose catastrophic risk, even existential risk, to humankind.

Objectives

The main objectives of the course are to:

1. Explain the main techniques used in obtaining accurate field data in volcanology, with particular emphasis on volcanotectonic structures and processes.
2. Describe in detail the main volcanic structures, including lava flows, pyroclastic layers, dikes, inclined sheets, sills, plugs (necks), shallow magma chambers (exposed as plutons), as seen in the field and how we go about studying them.
3. Explain the physical principles that control the formation and geometries of monogenetic volcanoes and, in particular, polygenetic (central) volcanoes. For the latter, the emphasis is on the role of the shallow magma chamber that acts as a source of the volcano.
4. Explain and illustrate the physical principles that control the formation of shallow magma chambers and their depths below the surface. The emphasis is on the mechanics of dike deflection into sills and the growth of sills into active magma chambers, but the thermal aspects are also considered.
5. Explain how magma chambers may develop magmatic excess pressure that results in magma-chamber rupture and dike injection. The focus is on the relationship between the shallow chamber and its deep-seated source reservoir(s).
6. Explain why many, and perhaps most, injected dikes and inclined sheets to not reach the surface to feed eruptions but rather become arrested on their paths at some crustal depths. Discuss the wide implications these observations and associated theories have for reliable assessment of volcanic hazards.
7. Explain the physical principles that control the formation of collapse calderas. Why do some caldera collapses result in eruptions while others do not? Why are caldera collapses in a given volcano rare in relation to the frequency of dike/sheet injections and eruptions of that volcano?
8. Explain the physical principles of very large eruptions; those that pose catastrophic risk, or even existential risk, to humankind

Limited places.

The textbook for the course is ‘Volcanotectonics: Understanding the Structure, Deformation and Dynamics of Volcanoes ‘(Cambridge University Press, 2020), that is available in a print and an electronic form from Amazon as well as from Cambridge University Press. It is strongly recommended that the participants have access to this textbook while taking the course.

In the course we will go through many of the worked examples in the textbook, as well as look at some of the numerous additional exercises. The aim of these is to provide the audience with quantitative skills to analyse and solve problems in volcanology, particularly within the main topics listed above.

The course follows basically the textbook “Volcanotectonics: Understanding the Structure, Deformation, and Dynamics of Volcanoes”. The students are expected to have this book while the course is running.  There will be some 12 pre-recorded lectures by Gudmundsson where the above topics are discussed with examples.  Each lecture is expected to be up to 20 minutes long. In addition, there will be 6 life webinars.  The length of each webinar is expected to be up to 2 hours.  The life webinars focus on topics of interest to the audience, as well as technical exercises, both field based and theoretical.

WEEK 1.

• – Lectures 1 & 2
• – Webinar 1
• – Textbook chapters 1 & 2

Main topics: Introduction and description of volcanic features and structures.  Definitions of basic terms, basic techniques used in the studies of active volcanoes. Basic techniques used in the studies of fossil (inactive) volcanoes.  Description of the main volcanic structures and features of interest to the course as seen in the field.

WEEK 2.

• – Lectures 3 & 4
• – Webinar 2
• – Textbook chapters 3 & 4

Main topics: Volcanotectonic  deformation and volcanic earthquakes.  Magma chambers as stress sources, the Mogi model, surface deformation, cavity models of chambers – analytical, numerical, and analogue models.  Background on earthquakes and seismic waves. Types of earthquakes. Volcanic tremors. Seismic monitoring of volcanoes.

WEEK 3.

• – Lectures 5 & 6
• – Webinar 3
• – Textbook chapters 5 & 6

Main topics: The principal volcanotectonic processes and formation and dynamics of magma chambers and reservoirs. Magma-chamber initiation, dike, sill, and laccolith emplacement. Caldera collapse. Formation and dynamics of deep-seated reservoirs. Formation and dynamics of shallow crustal magma chambers. Dynamics of double magma chambers.  Detection of magma chambers and reservoirs

WEEK 4.

• – Lectures 7 & 8
• – Webinar 4
• – Textbook chapter 7

Magma movement through the crust. Dike initiation and propagation paths.  The conditions for dike arrest.  Surface effects of dikes detected by geophysical measurements. Dike-fed fissure eruptions. Heat transfer from dikes and sills. Solidification of dikes and sills.

WEEK 5.

• – Lectures 9 & 10
• – Webinar 5
• – Textbook chapter 8

Dynamics of volcanic eruptions. Eruption sizes and frequencies.  Magma transport to the surface. Duration of eruptions. Mechanics of large explosive eruptions. Mechanics of large effusive eruptions.

WEEK 6.

• – Lectures 11 &1 2
• – Webinar 6
• – Textbook chapters 9 & 10

Formation and evolution of volcanoes, and forecasting their eruptions. Why are there any volcanic edifices? Intrusion and eruption frequencies of volcanoes. Shape and internal structures of volcanoes. Extinction of volcanoes. Volcanic unrest and associated shallow magma chambers.  Dike-induced deformation in layered rocks. Forecasting large eruptions.

Agust Gudmundsson

A leading volcanologist and structural geologist, Agust Gudmundsson worked for many years as a volcanologist in Iceland and then as a professor at universities in Norway, Germany, and England, as well as a visiting professor in France and Spain. His university courses are generally very highly rated by students. He has published more than 200 scientific papers, many of which are on active and fossil volcanoes and their structures, and has been instrumental in founding the new scientific field of volcanotectonics.  Most of his papers are available on ResearchGate and Google Scholar and many of his lectures for the general audience are on YouTube (Professor Agust Gudmundsson Youtube).  He is the author of 3 books on geology, namely: (1) Rock Fractures in Geological Processes (Cambridge University Press, 2011), The Glorious Geology of Iceland’s Golden Circle (Springer-Nature, 2017), and (3) Volcanotectonics: Understanding the Structure, Deformation, and Dynamics of Volcanoes (Cambridge University Press, 2020).

The course is delivered online through our easy-to-use Virtual Campus platform. For this course, a variety of content is provided including:

– eLearning materials
– Videos
– Interactive multimedia content
– Live webinar classes
– Texts and technical articles
– Case studies
– Assignments and evaluation exercises

Students can download the materials and work through the course at their own pace.
We regularly update this course to ensure the latest news and state-of-the-art developments are covered, and your knowledge of the subject is current.

Live webinars form part of our course delivery. These allow students and tutors to go through the course materials, exchange ideas and knowledge, and solve problems together in a virtual classroom setting. Students can also make use of the platform’s forum, a meeting point to interact with tutors and other students.

The tutoring system is managed by email. Students can email the tutor with any questions about the course and the tutor will be happy to help.

The course is in English and is aimed at the following: (1) undergraduate and graduate students in geology, geophysics, geochemistry, physical geography, and related fields; (2) civil authorities, scientists, engineers, and other professionals who deal with volcanoes and associated hazards in their work; (3) any person with a reasonable background in physical sciences or life sciences, either at university level or high-school level, who has great interest in volcanoes and how they work.  This includes science writers, journalists, and other people who work for the media.

While geological background is certainly helpful, it is not necessary in order to benefit from the course. This is partly because all the main concepts used are explained in the textbook and can be clarified in the webinars.

Many of the concepts used derive from physics. Again, these are all explained in detail in the textbook and can be further clarified in the webinars. The level of physics used is, with few exceptions, that of a typical high-school physics.

While many numerical model results will be discussed in the course, there is no numerical modelling in the course.  Most of the numerical models discussed are in the textbook. Thus, the focus is on understanding what the models mean as regards general volcanology, volcanotectonics, and related hazards.

Once a student finishes the course and successfully completes the assignments and evaluation tests, they are sent an accreditation certificate. The certificate is issued by Ingeoexpert to verify that the student has passed the course. It is a digital certificate that is unique and tamper-proof – it is protected by Blockchain technology. This means it is possible for anyone to check that it is an authentic, original document.

You will be able to download the certificate in an electronic format from the Virtual Campus platform. The certificate can be forwarded by email, shared on social networks, and embedded on websites. To see an example, click here.

While the course is on volcanology and related hazards, the geological and physical principles discussed and taught in the course have wide application in other fields.  The general principles discussed include fluid transport in rocks, rock-fracture initiation and propagation, stress, strain, and displacement fields, mechanical properties of rocks, geodetic measurements, earthquake mechanics, and the general conditions for rock failure.

As regards job prospects, the concepts and numerous examples discussed, clarified, and used in the course should be useful for people aiming to work, or already working, in the following fields: volcanology, structural geology, hazards, hydrogeology, geothermal research, tectonics, landslides, earthquakes/seismology, popular science writing, and the media.