Christopher Kilburn - Profile on Academia.edu (original) (raw)

Papers by Christopher Kilburn

Lunar and Planetary Inst., Twenty-Fourth Lunar and Planetary Science Conference. Part 2: G-M, 1993

Interactive web based volcanic hazard maps: Campi Flegrei caldera Italy

AGU Fall Meeting Abstracts, Dec 1, 2018

Surfaces of Aa Flow-Fields on Mount Etna, Sicily: Morphology, Rheology, Crystallization and Scaling Phenomena

IAVCEI Proceedings in Volcanology, 1990

Most of Etna’s historical lavas have produced aa flow-fields. Despite the classification, they su... more Most of Etna’s historical lavas have produced aa flow-fields. Despite the classification, they support a variety of surfaces in both the pahoehoe and aa categories. From observations of surface features at metre to submillimetre scales, two morphological series have been recognized: a sequence from pahoehoe to aa along a single flow, and an evolutionary trend among pahoehoe surfaces near boccas down a flow-field. The first series is more prominent and is superimposed on the second. Both series are associated with increasing crystallinity. The pahoehoe-aa sequence, however, is characterized by relatively higher crystallization rates and shear rates, indicating greater undercoolings and imposed stresses during emplacement. The identification of crystallization rate as a controlling factor demonstrates the influence of crystallization kinetics on lava development. The pahoehoe-aa transition also shows evidence of self-similar patterns at scales from at least millimetres to tens of centimetres, and may be accompanied by a self-feeding mechanism which couples large- and small-scale changes in lava rheology and shear rate.

An interrelated hazards approach to anticipating evolving risk

Communication during Volcanic Emergences: an Operations Manual for the Caribbean

DFID Project R7406: Protecting small islands by improving forecasting and warning

Assessing volcanic hazard at the most populated caldera in the world: Campi Flegrei, Southern Italy

Volcanos and Fate of Forecasting

A Fracture-Mechanical Model of Crack Growth and Interaction: Application to Pre-eruptive Seismicity

ABSTRACT

Fluid flow and degassing in high temperature magma

Dacitic volcanoes such as Mount St Helens are commonly associated with plinian eruptions. They ca... more Dacitic volcanoes such as Mount St Helens are commonly associated with plinian eruptions. They can also erupt magma as lava domes that, in addition to simple effusion, frequently pass through episodes of major collapse and can also explode in vulcanian eruptions under suitable increases in gas pressure. Both dome collapse and vulcanian events can propagate pyroclastic flows and so extend the hazardous range of a dome far beyond the radius of the dome itself. As magma rises in the conduit it becomes supersaturated with dissolved volatiles and, during decompression, exsolution occurs creating gas bubbles within the melt. The ability of gases to escape the rising magma depends strongly on its permeability. It is common in highly viscous magma for gas pressure to build up until, under a sufficient amount of depressurisation, the tensile strength of the magma is exceeded and fragmentation occurs. However effusion of lava domes requires magma to reach the surface in a relatively volatile ...

Controls on Recent Unrest at Campi Flegrei Caldera, Southern Italy

Campi Flegrei, in Southern Italy, is an active caldera that has shown signs of unrest since 1969.... more Campi Flegrei, in Southern Italy, is an active caldera that has shown signs of unrest since 1969. Because the caldera has a population of 400,000 people, it is especially important to understand the mechanisms driving the unrest and their implication for the probability of a future eruption. Since its last ignimbrite eruption 12,000 years ago (which produced the Neapolitan Yellow Tuff), volcanic activity in Campi Flegrei has consisted of numerous eruptions (volumes ~0.1 km3 or less) surrounding the inferred caldera rim. For at least the last 3,700 years, the caldera has been subsiding at mean rates of 14-17 mm per year, punctuated by two known periods of mean uplift (1430-1538 and 1969-Present). The first period produced a net uplift of about 30 m at the port of Pozzuoli and was followed in 1538 by the eruption of Monte Nuovo (20 million m3) some 4 km to the west. The second period has to date consisted of two episodes of uplift (in 1969-72 and 1982-84), each raising Pozzuoli by abo...

Studies of large volume landslides-Preface

Experimental Studies of Lava Dome Fracture

Renewed extrusion at andesitic to dacitic lava domes and collapses of these domes are usually pre... more Renewed extrusion at andesitic to dacitic lava domes and collapses of these domes are usually preceded by fracturing and frictional sliding of material in and around the lava dome and magma conduit. This is observed through the occurrence of shallow high frequency earthquakes. Samples of andesite from Mount Shasta in the Cascades, a typical material for both lava domes and shallow underlying country rock, have been deformed in compression and tension, at temperatures of up to 900°C, and under confining pressures of up to 70MPa. During these tests the axial load, sample deformation and acoustic emissions were recorded, in order to compare the results with field observations of deformation and short period seismicity at lava domes. Typical strengths at room temperature and pressure were 6MPa in tension, and 100MPa in compression. Increased temperatures increased the tensile strength, but reduced the compressive strength, whereas both strengths increased with increasing confining press...

Analysis of Martian Lava Flow Properties Using Three Complementary Models

Studies of lava flows on Mars must still rely largely on imaging data obtained by the Viking miss... more Studies of lava flows on Mars must still rely largely on imaging data obtained by the Viking mission. Therefore, flow morphology remains the prime data from which effusion and magma characteristics must be inferred. This study uses three complementary lava flow models to infer emplacement characteristics of several of martian flows. We have previously used these models to study some of Alba Patera's younger flows. Here we extend the scope of the work by analysing flows from the Elysium Planitia and further examining the sources of uncertainties in the models, including the effect of flow margin erosion. We will discuss how the models can be used together as a powerful analysis tool for extra-terrestrial lavas in general.

Etna erupts again; a VEST report of the March 1981 eruption of Mount Etna, Sicily

Earthquake Information Bulletin, 1981

Crustal controls on eruptions at large calderas

EGU General Assembly Conference Abstracts, Apr 1, 2018

Lava Flows on Alba Patera: Analysis of Flow Properties Using Three Complementary Models

Lunar and Planetary Science Conference, Mar 1, 1995

$Research paper thumbnail of Combined patterns of fracturing and deformation before volcanic eruptions$

Combined patterns of fracturing and deformation before volcanic eruptions

AGUFM, Dec 1, 2006

The rheological behaviour of basaltic lavas

Springer eBooks, 1985

Used in the nineteenth century as a cornerstone for the ‘Craters-of-Elevation’ hypothesis (Chapte... more Used in the nineteenth century as a cornerstone for the ‘Craters-of-Elevation’ hypothesis (Chapter 1), the fact that the fronts of some of Etna’s solidified lavas may be seen resting upon steep slopes, with dips of up to at least 35°, has since helped to initiate a fundamental advance in the understanding of lava flow evolution. Implicit in the earlier association between lava attitudes and ‘Craters-of-Elevation’ was the assumption that lavas, like large bodies of water, would continue to flow down an incline until being ponded behind an obstacle or within a depression, or until reaching a horizontal surface. In support of this contention, De Beaumont (1834) cited active Etnean lavas as examples of those which had been rarely observed to consolidate upon slopes with angles greater than 5° and which, in passing over steeper gradients, left behind only superficial veneers of solidified lava or coatings of scoriaceous debris. Hence the existence of old lavas lying on steep slopes was presented by De Beaumont as evidence that the underlying surface had been tilted to a higher angle after the emplacement of the flows.

Patterns and Predictability in the Emplacement of Subaerial Lava Flows and Flow Fields

Springer eBooks, 1996

Subaerial lava flows and flow fields show a restricted range of evolutionary sequences. The seque... more Subaerial lava flows and flow fields show a restricted range of evolutionary sequences. The sequences are related to the traditional classification of pahoehoe, aa and blocky lava, and each is distinguished by a characteristic association of morphological and dynamical features. These features, which include crustal growth and morphology, the formation of lava channels and tubes, the rate and style of flow advance, and the shape and emplacement time of a complete flow field, link processes operating over distances and time intervals that differ from each other by several orders of magnitude. Such links suggest that local observations on newly forming flows (e.g. styles of crustal development) might be sufficient for long-term forecasts of flow growth. The characteristic sequences reflect specific balances between the changing gravitational and pressure forces driving advance and increases in flow resistance due to solidification. The simplest emplacement regime is associated with aa flows, which persistently break their crusts during advance. Constrained by the condition for persistent crustal failure, first-order models provide good descriptions of aa growth trends, as well as a physical basis for forecasting flow behaviour. In particular, they permit estimates of maximum potential flow length and lengthening time from only the mean slope along the expected course of a flow.