James Hickey

James Hickey
University of Exeter (Cornwall Campus) · Camborne School of Mines

MSci Environmental Geoscience, PhD Volcanology & Geophysics

About

55
Publications
6,396
Reads
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365
Citations
Introduction
I am a geophysical volcanologist at the Camborne School of Mines at the University of Exeter (Cornwall campus). My research interests are in the processes controlling the dynamics of active and restless volcanoes and the geophysical signals they produce, with an aim of helping to improve eruption forecasting capabilities. https://drjameshickey.co.uk/
Additional affiliations
October 2015 - April 2016
University of Bristol
Position
  • PostDoc Position
September 2011 - present
University of Bristol
Position
  • PhD Student
Education
October 2007 - June 2011
University of Bristol
Field of study
  • Earth Sciences

Publications

Publications (55)
Conference Paper
Full-text available
Understanding the mechanical behaviour of melt reservoirs is vital for advancing geophysical models that aim to constrain the evolution of subvolcanic systems and inform hazard monitoring and mitigation. From geophysical and petrological studies, large melt-dominated (magma) reservoirs are difficult to sustain over long periods of time. Melt is mor...
Article
Full-text available
Investigating the temporal development of magma reservoir pressure and associated surface displacements can reveal fundamental aspects of subsurface magmatic processes and aid in eruption forecasting. The limitation with existing volcano deformation models is that they typically ignore magma intrusion dynamics and focus on the response of surroundi...
Article
How and why magmatic systems reactivate and evolve is a critical question for monitoring and hazard mitigation efforts during initial response and ongoing volcanic crisis management. Here we report the first integrated petrological results and interpretation provided to monitoring authorities during the ongoing eruption of Cumbre Vieja, La Palma, C...
Conference Paper
Full-text available
For the purpose of forecasting eruptive activity at volcanoes that host active hydrothermal systems (HTS), it is important to discriminate anomalies caused by processes related to either magma or fluid Pow. Here we develop 2D axisymmetric numerical models to study magmatic and non-magmatic unrest at Mt. Ruapehu where ascending fluids feed an active...
Preprint
Full-text available
The first products of the current Cumbre Vieja eruption comprise simultaneous tephra fall from near-continuous, gas-rich eruption plumes and lava flows. From combined field, petrographic and geochemical analyses we identify: low percentage mantle melts with a variably-equilibrated multimineralic crystal-cargo and compositional fractionation by erup...
Article
Full-text available
Volcanoes undergoing unrest often produce displacements at the ground surface, providing an important window to interpret the dynamics of the underlying magmatic system. The thermomechanical properties of the surrounding host rock are expected to be highly heterogeneous, with key physical parameters having a strong dependence on temperature. Deform...
Conference Paper
Full-text available
As volcanic systems undergo unrest, understanding the conditions required for reservoir failure, the associated timescales, and the links to geophysical observations are critical when evaluating the potential for eruption. The characteristics and dynamics of a pressurised magmatic system can be inferred from episodes of surface deformation, but thi...
Conference Paper
Full-text available
Understanding the physical properties of magma reservoirs and their fluid/mechanical behaviour is crucial for improving geophysical models. New evidence suggests that large bodies of magma are difficult to maintain for an extended time period and that melts may instead reside within crystal-mush reservoirs which consist of variably packed framework...
Conference Paper
Full-text available
Investigating the temporal development of magma reservoir pressure and associated surface displacement can reveal fundamental aspects of subsurface magmatic processes and aid in eruption forecasting. Magma fluid dynamics, rather than the widely used kinematic techniques, should be incorporated into magmatic modelling to track the temporal developme...
Conference Paper
Full-text available
Pre-eruptive electrical signals at active volcanoes are generally interpreted in terms of electrokinetic processes in the subsurface. Spatio-temporal self-potential (SP) signals can be caused by strain-induced fluid flow in volcanic aquifers, however, previous studies lack the quantitative assessments of these phenomena and the underpinning poroela...
Article
Full-text available
We invert intraeruptive ground displacements recorded between 2003 and 2005 on Montserrat to shed light on the magmatic plumbing system of Soufrière Hills Volcano. Incorporating 3‐dimensional crustal mechanical and topographic data in a finite‐element model, we show that the recorded displacements are best explained by a southeastward dipping (plun...
Conference Paper
Full-text available
Episodes of ground deformation, relating to the unrest of a volcanic system, are often readily identifiable within geodetic timeseries (e.g. GPS, InSAR). However, the underlying processes facilitating this deformation are more enigmatic. By modelling the observed deformation signals, the ultimate aim is to infer characteristics of the deforming res...
Article
Full-text available
High rates of volcano surface deformation can be indicative of a forthcoming eruption, but can also relate to slope instability and possible flank collapse. Tungurahua volcano, Ecuador, has been persistently active since 1999 and has previously experienced catastrophic flank failures. During the ongoing eruptive activity, significant surface deform...
Conference Paper
Full-text available
Episodes of ground deformation, relating to the unrest of a volcanic system, are often readily identifiable within geodetic timeseries (e.g. GPS, InSAR). However, the underlying processes facilitating this deformation are more enigmatic. By modelling the observed deformation signals, the ultimate aim is to infer characteristics of the deforming res...
Conference Paper
Full-text available
A pressurized magmatic intrusion will strongly interact with its surrounding by provoking changes in the subsurface stress and strain fields. As a result, nearby aquifers can experience pore pressure variations which in turn drive fluid motion. Induced subsurface flow can cause variations in the electrical self-potential (SP). The SP method has bee...
Poster
Full-text available
Preliminary study into how EDM records deformation patterns, with application to the Soufriere Hills Volcano, Montserrat. This will feed into a larger study into modelling deformation at SHV utilising co-analysis of both GPS and EDM data.
Article
Full-text available
Inelastic rheological behavior, such as viscoelasticity, is increasingly utilized in the modeling of volcanic ground deformation, as elevated thermal regimes induced by magmatic systems may necessitate the use of a mechanical model containing a component of time‐dependent viscous behavior. For the modeling of a given amplitude and footprint of grou...
Article
Full-text available
Global Synthetic Aperture Radar (SAR) measurements made over the past decades provide insights into the lateral extent of magmatic domains, and capture volcanic process on scales useful for volcano monitoring. Satellite-based SAR imagery has great potential for monitoring topographic change, the distribution of eruptive products and surface displac...
Chapter
Full-text available
Volcanic eruptions are often preceded by small changes in the shape of the volcano. Such volcanic deformation may be measured using precise surveying techniques and analysed to better understand volcanic processes. Complicating the matter is the fact that deformation events (e.g., inflation or deflation) may result from magmatic, non-magmatic or mi...
Article
Full-text available
Ground deformation often precedes volcanic eruptions, and results from complex interactions between source processes and the thermomechanical behaviour of surrounding rocks. Previous models aiming to constrain source processes were unable to include realistic mechanical and thermal rock properties, and the role of thermomechanical heterogeneity in...
Article
Full-text available
Deformation at Cotopaxi was observed between 2001 and 2002 along with recorded seismicity beneath the north-east (NE) flank, despite the fact the last eruption occurred in 1942. We use Electronic Distance Meter (EDM) deformation data along with the patterns of recorded seismicity to constrain the cause of this unrest episode. To solve for the optim...
Conference Paper
Volcanic eruptions are often preceded by periods of unrest, where the behaviour of the volcano deviates from a background level towards one of increasing concern [Phillipson et al., 2013]. Understanding what causes and contributes to unrest is a key challenge in volcanology today, influencing risk mitigation and hazard forecasting. Deformation of...
Article
Full-text available
Cerro Uturuncu is a long-dormant, compositionally monotonous, effusive dacitic volcano in the Altiplano-Puna Volcanic Complex (APVC) of SW Bolivia. The volcano recently gained attention following the discovery of an similar to 70 km diameter Interferometric Synthetic Aperture Radar (InSAR) anomaly roughly centred on its edifice. Uturuncu dacites, e...
Article
Full-text available
Volcanic deformation during an unrest episode can provide valuable insights into potential magmatic plumbing system dynamics. Paramount to this is a model linking the recorded ground movement to the causative source at depth. Most models employ analytical techniques due to their simplicity, but these are limited in their approach due to a number of...
Conference Paper
Volcanic deformation during an unrest episode can provide valuable insights as to potential magmatic plumbing system dynamics. Paramount to this is a model linking the recorded ground movement to the causative source at depth. Despite a number of necessary assumptions, such models have been useful in extracting different source characteristics at v...
Conference Paper
Uturuncu volcano in southern Bolivia has been steadily inflating since at least 1965, and combined with shallow seismicity and near-summit active fumaroles represents a volcanic system showing significant signs of unrest. This study focuses on the mechanism driving the 70 km wide region of ground uplift. Using Finite Element Analysis we test for fi...
Article
This paper focuses on the driving mechanism behind a 70 km wide region of ground uplift centered on Uturuncu volcano, in the Altiplano-Puna region of southern Bolivia. We present a series of forward models using finite element analysis to simultaneously test for first-order parameters that help constrain a viable model for the observed maximum line...
Conference Paper
This study focuses on a Finite Element Analysis of the world's largest recorded ground deformation anomaly in the Altiplano-Puna region of southern Bolivia. We present a series of forward models to construe the 70 km wide ground displacement field identified by satellite geodesy between 1996 and 2000, with a mean inflation rate of ~1.5 cm/yr, cente...
Conference Paper
This study focuses on a Finite Element Analysis of large-scale ground deformation at Uturuncu volcano in the Altiplano-Puna region of southern Bolivia, for the period 19th May 1996 to 24th December 2000. The amplitude of the line-of-sight displacement from InSAR is 7.4 cm, with a wavelength of around 80 km for that period. We present a series of fo...

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Projects

Projects (2)
Project
Construct and apply enhanced deformation models to episodes of ground deformation to elucidate the underlying processes and rheological behaviour.
Project
My PhD research is focussed on assessing the role of viscoelasticity in volcanic ground deformation models, with application to the Taupo Volcanic Zone, New Zealand.