Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Geophysics

Supervisor

Dr. Robert Shcherbakov

Abstract

Volcanism is an important mechanism by which internal heat is transported to the Earth's surface and volcanic eruptions are the results of the dynamics of a complex system and are characterized by non-trivial temporal correlations. Understanding the processes involved in volcano formation and magma ascent are crucial to develop better hazard assessment techniques. This study focuses on three main points: understanding caldera formation in the solar system, investigating the global temporal behaviour of volcanic eruptions and understanding the nonlinear interactions taking place in the solid crust which lead to an eruption.

In chapter 2, I first examine the distribution of caldera diameters on Earth, Mars, Io and Venus by performing a scaling analysis using the mean caldera diameter as a scaling factor. I fi
nd that their probability densities can be described by a universal distribution that can be approximated by a Generalized Extreme Value distribution. This scaling implies that a similar process governs caldera formation throughout the solar system.

In chapter 3, I investigate the distribution of interevent times between eruptions for active volcanoes on Earth. When rescaling the axis using the mean rate of volcanism, the distributions collapse into a single one, the log-normal distribution. This scaling implies that the processes governing volcanic eruptions on Earth are similar and are independent of the type of volcanism and location, which emphasizes the importance of studying volcanism by modelling a universal behaviour.

In the last chapter, I take a modelling approach to study the interactions between the magma and the crust. I define a lattice gas cellular automata model where the magma is represented by discrete particles. In this model, magma propagates through the crust and fracturing occurs until it reaches the top of the crust and an eruption or a cascade of eruptions occur. I study the statistical behaviour of eruptions in the model and observe similar size and temporal behaviours that have been observed on active volcanoes.


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