Post on 20-Jul-2020
Logo here?Kraf a fumarole. ©Yan Lavallee, University of Liverpool.
Crossing the Scientific and
Technological Frontier
from Solid Rock to Magma
KRAFLA MAGMA TEST BED (KMT)
One of the great challenges in understanding Earth’s crustal processes is the interface between the aqueous fluid-bearing or hydrothermal regime and the silicate melt-bearing or magmatic regime. The migrations of magma and fluid are the agents of mass and heat transfer within the crust and to the surface. Humans experience this as volcanic eruptions, geothermal energy, and ore deposits.
The rate of heat loss from magma through a
surrounding hydrothermal system controls the
lifetime of the magma body and the energy available
for extraction from the hydrothermal system. We
can imagine a magma body as a thermos flask
where the wall is the crystallized magma itself. This
insulating wall is the critical interface of transition
from magmatic to hydrothermal systems, but at very
high temperatures its rock wall can deform so any
fractures will quickly heal. Without melt or fluid to
flow, heat transfer would be by conduction, which is
mostly dependent on thickness of the wall. The high
temperature face of this zone is hypothesized to be
crystallizing magma and the low temperature face is
thought to contain growing fluid-filled cracks. The
answer to how magma and hydrothermal systems are
coupled lies in this zone.
Geothermal drilling in the Krafla Caldera, Iceland,
serendipitously hit rhyolite magma at a depth of only
Introduction
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2100 m. This was a major breakthrough and provides
unprecedented opportunities allowing us to:
• closely observe, sample, and manipulate the
transition zone in order to rigorously test
concepts of volcanic systems
• develop improved or new monitoring
techniques for volcanology
• push drilling and sensor technology to the
crust’s high-temperature maximum
• explore the roots of geothermal systems and
the potential for direct energy extraction from
magma — the ultimate geothermal resource.
What is proposed is more than a drilling project. It
is a cluster of coordinated, multidisciplinary efforts
encompassing:
• borehole and sample observations coupled with
large-scale experimental studies
• linked surface geophysical and geochemical
observations
• advanced geothermal energy technology
• sensor development for extreme environments
• advanced volcanic eruption forecasting.
It combines the serendipity of the Krafla discovery
with the growing pressure–temperature overlap of
drilling, volcanology, and laboratory experimentation.
This is the Krafla Magma Testbed (KMT).
The concept of crossing a frontier is apt, because
exploration of the interior of our planet has received
less attention than exploration of outer space or
the atom. With our burgeoning population, we need
to pay more attention to the frontiers beneath us.
This attention requires multinational and multi-
stakeholder partnerships such as the Ocean Drilling
Program and now the International Continental
Scientific Drilling Program (ICDP), of which KMT is a
part. The frontier between solid and molten Earth is
one through which all of the Earth’s crust has passed,
but our observations have not.
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Globally, governments spend large sums on volcano
monitoring because with proper monitoring, the risk of
disaster can be reduced. Volcanoes give early warning
of eruption by:
• increases in small earthquakes
• inflation of the volcano on a scale of centimeters
(or meters in extreme cases)
• changes in the amounts and chemistry of
escaping gases.
Such signs are readily detected by instrument networks
at the surface and are termed unrest.
The World Organization of Volcano Observatories
(WOVO) has 79 members from 33 countries. National
expenditures for observatories range from tens of
millions Euros per year for prosperous countries
with high vulnerabilities to modest operations that
are part of weather stations in other cases. Average
fatalities per year are under one thousand, modest by
comparison with floods and earthquakes, but volcanic
catastrophes with hundreds of thousands killed
and economic losses in the hundreds of billions are
possible. Eruptions on this huge scale are geologically
common but have not occurred in modern times.
Today, most volcanoes that threaten significant
populations or air routes are monitored with arrays
of telemetered instruments to detect and measure
unrest. However, the signals measured are only
proxies for what the magma beneath the volcano is
doing. This has never been directly observed, so we
are in a worrying situation where decisions of great
consequence are based on models that are untested.
Volcano monitoring
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By drilling through the rock–magma interface and into
magma, we can:
• establish where and under what conditions magma
is stored beneath a volcano
• stimulate its boundary region by fluid injection to
see whether the result is indeed the inferred unrest
• and ultimately place sensors near and even in
magma to provide direct measurement of a rise in
temperature or increase in pressure that could lead
to eruption.
The latter development could be a complete game-
changer in monitoring strategy, providing greater
assurance of timely and accurate warning, and perhaps
shifting to more efficient, less labour-intensive
monitoring strategies.
A simple and certain result will be the ground-truthing of
geophysical techniques such as seismic, electromagnetic,
gravity, and geodetic measurements that are used to infer
the presence of magma and transient changes in magma
pressure. The threat of eruption is deemed to be higher
if the magma is closer to the surface the — a shorter
warning time for its arrival at the surface. The fact that
magma under Krafla was discovered at half the predicted
depth is therefore reason enough to seriously re-evaluate
existing volcano monitoring methods. The KMT will
develop a World Volcano Model, a world standard for
hazard assessment, monitoring, and data interpretation,
comparable to that being developed for earthquakes.
Geothermal potential
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In many ways, geothermal energy is an ideal energy source for the future
because it is:
• renewable (unlike fossil fuels)
• low to net zero in CO2 emission
• continuous — independent of diurnal and seasonal cycles
(unlike solar, wind, and hydroelectric)
• small in footprint and ecological impact because the production facility is
sited on the fuel source
• free from the accident and spill hazards of transporting fossil fuels and
nuclear waste, and from the major ecological impact of hydropower
reservoirs.
Despite its many advantages, geothermal energy currently makes up only
about 0.1% of global power production. Geothermal power plants are
relatively inefficient in converting heat to electricity compared to fossil
fuel and nuclear plants, because they use lower temperature natural steam.
They lack economies of scale because conventional practice yields only tens
or hundreds of MWe production per geothermal field. Also, the resource is
restricted geographically and not transportable, except by transmission of
the electric power produced. KMT will test the feasibility of extracting heat
directly from magma rather than indirectly from rocks heated by magma.
This will increase the heat energy extractable from a geothermal field by an
order of magnitude and the efficiency of conversion to electricity by a factor
of two or three. Meanwhile, instead of transporting fuel to conveniently
located power plants, the electricity can be transmitted to users by low-
loss, high-voltage DC cables, including submarine cables. The demand for
development and production of high-voltage DC transmission systems is
currently driven by ocean wind-power farms, but high-grade geothermal
fields can quickly benefit as well.
As the drive to reduce anthropogenic CO2 emission increases, the
development of geothermal energy must also increase. The use of
supercritical steam heated directly by magma will dramatically change the
economics of geothermal energy. Volcanic ranges and islands could become
national and international power factories. In addition, the reduction of
eruption risk is a possible collateral benefit.
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Now is the time to seize upon the convergence of
multiple fields of science and engineering with a
magma testbed. Geothermal drilling and flow testing,
which by nature perturb the system and measure
the response, have reached the magmatic hearth.
Real-time volcano monitoring techniques have been
revolutionized through conversion from analog
to digital systems and the advent of geographical
positioning systems (GPS) and interferometric synthetic
aperture radar (ISAR) technology. This has in turn led to
a blossoming of models for magma that must be tested
to be reliably used. Large-scale laboratory experiments
with rock under magmatic conditions and sophisticated
finite-element fluid-dynamic models can now inform
us of both natural and drilling induced perturbations
to the magmatic system. In turn, new observations
through drilling can inform new laboratory experiments.
Sensors that are being developed to monitor conditions
within jet and rocket engines, which have the same
temperature regime as magma, can be applied to direct
monitoring.
The result of the KMT will be that for the first time we
will have:
• a real understanding of time-dependent behavior
of magmatic systems in response to pressure and
temperature changes and fluid injection
• magma engineering that could be used to greatly
increase the extraction of geothermal energy
• the possibility of reducing the volume of shallow
eruptible magma in the system, thereby reducing
eruption risk.
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Magma manipulation
We will be working at the limits of technology in
drilling, materials, and sensor systems in a dynamic
environment. It extends from crystallizing magmas
at 900°C, 50 MPa, and 2100 m depth transitioning
upward within 30 m abruptly to solid rock at 350°C
and then through a producing geothermal system to
ambient atmospheric temperature and pressure at the
surface. As well as providing an extreme environment
for unprecedented research and for developing the
commercial geothermal opportunity of supercritical
steam, Krafla will drive innovation from Technology
Readiness Level 1 (TRL1), basic scientific principles, to
TRL 10, qualified tested and operational technology.
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Technology transfer from the Kafla Magma testbed
Next stepsWe are actively engaged in raising 20 m Euros from
public- and private-sector sources in multiple countries to
launch the first drilling and engineering phase of the KMT.
Related scientific investigations have already begun in Italy,
Germany, New Zealand, United States and Iceland.
TRL 1–4 Develop the basic theories of magma crystallization, heat migration and circulation of fluids at a magma–rock interface through direct in situ observations.
Development of functions to test in situ technology including laboratory simulation and validation of indirect and direct measurement and geophysical models.
Outcomes New theories on magma crystallization and heat flux
New models for the magma– fluid– rock interface
Feasibility of reducing volume of eruptible magma through energy extraction
TRL 3–6 Installation of sensor networks and validation in different geo-environments
Joining the best practice in the geothermal and volcanological environment
Outcomes New sensor systems for hot, acid and dynamic geological environments
Real-time calibrations for operational geophysics including intentional stimulation and detection of volcanic unrest
Transfer of application from materials technology
TRL 6–10 Demonstration of the use of supercritical steam in an active magma chamber environment
Demonstration of use of sensor systems in an active magma environment for enhanced real-time volcano monitoring
Outcomes Commercialization of supercritical steam geothermal systems
Sensor systems to model and help to predict volcanic eruptions
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About the authorsDonald Bruce Dingwell is President of the International Association of Volcanology
and Chemistry of Earth’s Interior and 3rd Secretary General of the European Research
Council. He is Director and Professor, Earth and Environment, Ludwig Maximilian
University of Munich and was President of the European Geosciences Union. A
foremost expert on laboratory measurement of magmatic properties, he is largely
responsible for development of the field of experimental volcanology.
John C Eichelberger is Principal Investigator for KMT, Professor of Geology at
University of Alaska Fairbanks, and Vice President Academic of University of the
Arctic. He was Volcano Hazards Program Coordinator for the US Geological Survey.
He has served as PI on four scientific drilling projects on volcanoes, and investigator
on two others including the successful coring of a 1200oC lava lake in Hawaii. He
received the European Geosciences Union’s award for work in natural hazards science
in 2015.
John N Ludden, CBE, is Executive Director of the British Geological Survey and Chair,
Earth Science Europe. He has held numerous science direction and management
posts, including Director of the Earth Sciences Division at the French National Centre
for Scientific Research (CNRS) and President of the European Geosciences Union
(EGU).
Charles Mandeville is Program Coordinator for the US Geological Survey’s Volcano
Hazards Program. He manages the five volcano observatories of the US and guides
the underlying scientific research and is also a Member of the Steering Committee for
the Global Volcano Model. He is well known for his work on magmatic volatiles.
Sigurður H Markusson is Geochemist and Project Manager of Landsvirkjun National
Power Company’s Krafla Geothermal Project. Landsvirkjun, as operator of the Krafla
geothermal field and power plant, is the key industrial partner of KMT and has drilled
through the rock melting point in three separate boreholes.
Paolo Papale is former Director of Volcanology for Italy’s Istituto Nazionale Geofisica
e Vulcanologia (INGV). He currently leads the Volcano Hazard Centre at INGV where
he is responsible for volcano hazard studies and assessment on some of the most
active, populated, and dangerous volcanoes in the world.
Freysteinn Sigmundsson is Professor of Geophysics at Nordic Volcanological Centre,
Institute of Earth Sciences, University of Iceland. He leads and has led a number of
major volcanological project consortia in Europe and is widely recognized for his
work on volcano deformation and plate tectonics.
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ContactHjalti Páll Ingólfsson: hpi@georg.cluster.is
John Eichelberger: jceichelberger@alaska.edu