The Earth System and the Role of Magmatism

During its evolution, the Earth has physically and chemically differentiated, as the densest elements were drawn into the core and the lightest ones buoyantly rose to the surface, establishing the geosphere, blanketed by the hydrosphere and atmosphere. Biochemical reactions at the intersection of these spheres spurred the development of the biosphere. Most recently, the population surge at the end of the second millennium fostered the creation of the technosphere (UNESCO 2018). With this rapid growth, the Earth’s resources have been extensively exploited, and the connectivity between the spheres has been disturbed, prompting climate change and a population increasingly at risk of natural hazards (Small and Naumann Reference Small and Naumann2001). As geoscientists in the third millennium, it is our duty to quantitatively describe the Earth system and find solutions to maximize resource utilization, minimize our impact, and so, increase our adaptability and resilience towards a sustainable existence (Deutsche Akademie der Naturforscher Leopoldina 2022).

Since the establishment of the theory of plate tectonics, which may be regarded as the last major revolution in Earth sciences, we have obtained a quantitative process-based understanding of the Earth’s dynamics (Cloetingh et al. Reference Cloetingh, Sternai, Koptev, Ehlers, Gerya, Kovács, Oerlemans, Beekman, Lavallée and Dingwell2023). Magmatism and volcanism are primary agents in the Earth system; they are responsible for the transfer of mass and heat through the lithosphere and into the outer spheres. The shallow transport of magma is powered by the presence of volatiles, which greatly contribute to the buoyancy of magma. As magma ascends through the Earth, the solubility of volatiles in magma decreases, causing vesiculation (i.e., formation of gas bubbles), which impacts the properties of magma (including its buoyancy and viscosity) and so its mobility and eruptibility. Thus, volcanic eruptions are the expressions of magma surging to the Earth surface due to excess gas. It has been estimated that about 10% of magmas erupt, whilst 90% stall at depth to form plutonic rocks, constructing the Earth’s crust (Schmincke Reference Schmincke2004). Such ratios vary depending on the tectonic setting, yet methods to accurately probe and quantify magma transport and storage have been beyond our grasp. With the advent of satellite-borne remote sensing observations, volcanoes have been the subject of extensive scrutiny, which has provided us with much improved quantitative budgets of volcanic emissions worldwide (e.g., Werner et al. Reference Werner, Fischer, Aiuppa, Edmonds, Cardellini, Carn, Chiodini, Cottrell, Burton, Shinohara and Allard2019). The principal outputs are volcanic ash and gas; primarily H₂O (>650 Tg/yr, although with high uncertainty due to its abundance in the atmosphere; Fischer et al. Reference Fischer, Arellao, Carn, Aiuppa, Galle, Allard, Lopez, Shinora, Kelly, Werner, Cardellini and Chiodini2019), followed by CO₂ (∼300 Tg/yr; Werner et al. Reference Werner, Fischer, Aiuppa, Edmonds, Cardellini, Carn, Chiodini, Cottrell, Burton, Shinohara and Allard2019), sulphur compounds (∼20 Tg/yr; Carn et al. Reference Carn, Fioletov, McLinden, Li and Krotkov2017), and smaller concentrations of halogens (bromine, chlorine etc.) and other molecules, which can react to form aerosols (Aubry et al. Reference Aubry, Staunton-Sykes, Marshall, Haywood, Abraham and Schmidt2021; Roberts et al. Reference Roberts, Vignelles, Liuzzo, Giudice, Aiuppa, Coltelli, Salerno, Chartier, Couté, Berthet, Lurton, Dulac and Renard2018) upon transport in the atmosphere, impacting the Earth’s outer spheres (Figure 1). Ninety-nine percent of carbon on Earth is stored in the subsurface; it is commonly incorporated into and/or remobilized by magmatic activity, which can release it into the atmosphere and hydrosphere. Volcanic eruptions have been advocated as culprits for both the cooling and warming of the Earth’s atmosphere (Robock Reference Robock2000; Toon Reference Toon1980). They thus disrupt the climate, ecosystems and civilization; sometimes positively – via increased fertility of soil (Fiantis et al. Reference Fiantis, Ginting, Nelson and Minasny2019), blooming of fisheries (e.g., Parsons and Whitney Reference Parsons and Whitney2012), or increased artistic productivity (Chester Reference Chester2005) – but most commonly negatively, depending on the scale of events, which may range from mild disruption to infrastructure and daily activities, to the obliteration of civilization (Grattan and Torrence Reference Grattan and Torrence2016; Self Reference Self2006).

Figure 1. Photograph of a volcanic plume during the 2010 Eyjafjallajökull eruption (Iceland), indicating some of the primary outputs of volcanic emissions. Credit: Photo from Magnus T. Gudmundsson (University of Iceland).

Volcanic Hazard Assessment and Risk Mitigation

Magmatic unrest and volcanic activity may generate a wide spectrum of volcanic hazards, ranging from toxic gas emissions to volcanic ash plumes that can circle the globe, to searing pyroclastic density currents, mud flows and mass movements (landslides, rock falls, sector collapses) of volcanic edifices that can travel several tens to hundreds of kilometres in a few hours and cause distal tsunamis (Sigurdsson et al. Reference Sigurdsson, Houghton, Rymer, Stix and McNutt1999). These hazards pose a potential threat to approximately 15% of the Earth’s population (Freire et al. Reference Freire, Florczyk, Pesaresi and Sliuzas2019). At present, nearly one billion people live within 100 km of volcanoes active during the last 10,000 years – a number which has nearly doubled in the last two decades (Loughlin et al. Reference Loughlin, Sparks, Brown, Jenkins and Vye-Brown2015; Witham Reference Witham2005). The most common aftermaths of volcanic activity include loss of human life, respiratory illness, death of crops and livestock, and economic losses due to damage or destruction of infrastructure. Since ad 1500, we know of 278,368 fatalities (Brown et al. Reference Brown, Jenkins, Sparks, Odbert and Auker2017), and in the twentieth century volcanic events have killed approximately 98,000 people while affecting about 5.6 million people worldwide (Witham Reference Witham2005). In terms of economic impact, the consequences vary widely; the recent disruption caused by the 2010 eruption of Eyjafjallajökull volcano in Iceland forced the cancellation of over 100,000 flights, with financial repercussions estimated at approximately €3.3 billion (Mazzocchi et al. Reference Mazzocchi, Hansstein and Ragona2010). So, even in the case of modestly sized eruptions we must consider that their impact is set to increase as the Earth’s population spreads towards active volcanoes. Yet, the geologic record indicates that the scale and reach of these hazards extends far beyond what we have historically witnessed. For instance, a large event (e.g., >100 km³ of erupted volume) has ∼4% chance of occurrence in this century (Papale Reference Papale2018; Papale and Marzocchi Reference Papale and Marzocchi2019), and it has been argued that we are not adequately prepared for the occurrence of a super-eruption, which would cause global climatic disturbance (Cassidy and Mani Reference Cassidy and Mani2022). The largest ash dispersal event since the last ice age, the 1815 eruption of Tambora (Indonesia), caused widespread crop failures and famine after global average temperatures dropped by ∼1°C (Stothers Reference Stothers1984). Given that world food reserves total an estimated 74 days (FAO et al. 2012), such global disruption of temperature could be catastrophic.

In the last four decades, volcanology has undergone a revolution in quantitative observations of volcanic processes, thanks to sophisticated monitoring methods and advances in computational power as well as intelligent, machine-learning algorithms. Perhaps unsurprisingly, the most common question asked to a volcanologist is: can we predict volcanic eruptions? The short answer is no, but we can sometimes forecast the onset of eruptions (Bell et al. Reference Bell, Naylor, Hernandez, Main, Gaunt, Mothes and Ruiz2018; Voight et al. Reference Voight, Sparks, Miller, Stewart, Hoblitt, Clarke, Ewart, Aspinall, Baptie and Calder1999) or transitions in eruptive behaviour (De la Cruz-Reyna and Reyes-Davila Reference De la Cruz-Reyna and Reyes-Davila2001; Lavallée et al. Reference Lavallée, Meredith, Dingwell, Hess, Wassermann, Cordonnier, Gerik and Kruhl2008), depending on the character of precursory signals (Poland and Anderson Reference Poland and Anderson2020). Although to date our forecasting efforts are frequently undertaken with hindsight, better monitoring network cover and faster data processing capabilities are improving this situation. Importantly, the acquisition and analysis of long-term datasets have already provided us with a view of the recurrence rate of volcanic activities at particular volcanoes (e.g., Carter et al. Reference Carter, Rietbrock, Lavallée, Gottschämmer, Moreno, Kendrick, Lamb, Wallace, Chigna and De Angelis2020) in a range of settings (Marzocchi et al. Reference Marzocchi, Selva and Jordan2021; Papale et al. Reference Papale, Garg and Marzocchi2022), and integrated analysis of multi-parametric systems has given us increasing detail of shallow magma transport and precursory signals leading to volcanic eruptions (Sigmundsson et al. Reference Sigmundsson, Pinel, Grapenthin, Hooper, Halldórsson, Einarsson, Ófeigsson, Heimisson, Jónsdóttir and Gudmundsson2020). Yet, at this stage, we do not have the ability to answer where?, how? and for how long? an eruption is likely to occur. These are key questions that need to be addressed to improve volcanic hazard assessments and, in turn, adequately mitigate the risks. But to answer these questions, the community requires continuous, multi-parametric monitoring at a greater number and broader diversity of active volcanoes worldwide. It must validate processing methods and ground-truth observations. Ultimately, it must constrain and quantify the state of magma – an environment for which we, to date, possess only indirect knowledge. Direct knowledge of the state, distribution and properties of magma will enable the development of robust, quantitative, predictive tools that comprehensively integrate magma generation, transport and eruptions in the Earth system.

Our models of magma genesis, storage and transport rely in large part on somewhat indirect evidence exposed in the geologic record – both from eroded batholiths (magma bodies crystallized in the subsurface) and eruptive products – and from laboratory measurements which have helped constrain the properties (chemistry, petrology, density, diffusivity, viscosity, etc.) of magma and igneous rocks at natural conditions (Dingwell Reference Dingwell2006; Ghiorso and Gualda Reference Ghiorso and Gualda2015; Giordano et al. Reference Giordano, Russell and Dingwell2008; Lavallée and Kendrick Reference Lavallée and Kendrick2021). Examination of these rocks has highlighted that magma reservoirs organize in different configurations depending on the production rate of magmatism and the level of interaction with the surrounding rocks. Magma bodies range in size and can be fully molten, or a complex amalgamation of partially crystallized magma mushes (Cashman et al. Reference Cashman, Sparks and Blundy2017). Despite decades of efforts in volcano geophysics, we cannot confidently detect, locate nor image magmatic bodies in the subsurface. Whilst some studies have inferred the presence of magma in the Earth’s crust, the location and size of magma reservoirs remain speculative, as our models have never been ground-truthed; hence, models remain models. Common methods employ passive and active seismicity, ground deformation, gravity, ground resistivity and magneto telluric surveys, and they sometimes provide estimates concurrent with petrological estimates of magma storage conditions during the studies of eruptive products. Yet, such constraints are somewhat biased towards larger storage bodies and thus only coarsely accurate (in the range of ±∼1–2 km) due to many unknowns. The ability to test our models on a system with known (directly monitored) rock and magma properties would drastically change this situation.

Probing the Subsurface and the Roof of Magma Bodies

Coring and drilling can radically improve knowledge of the subsurface by supplementing geophysical datasets with direct observations and in situ measurements; this costly practice is primarily undertaken by the industry (oil and gas, geothermal, etc.), is comparatively rare in active volcanic areas, and even scarcer in the service of monitoring volcanoes. Nevertheless, drilling in volcanic provinces, such as Iceland, Italy, New Zealand and Mexico, has exposed the diversity of reservoir rocks, showing extensive variations in rock types, in degree of alteration, fracture networks, and in geothermal gradients; dictated by tectonic setting and the circulation and action of hydrothermal fluids (e.g., Mortensen et al. Reference Mortensen, Egilson, Gautason, Arnadottir and Guðmundsson2014). The circulation of hydrothermal fluids is driven by the thermal gradient, imparted by heat production in the Earth’s interior and heat loss at the surface (e.g., Lister Reference Lister1980). Earth’s heat loss has been estimated at 46 ± 3 TW (Jaupart et al. Reference Jaupart, Labrosse, Lucazeau, Mareschal and Schubert2015). Heat is heterogeneously lost depending on the composition and thickness of the crust and the occurrence of magmatism. On continents, non-volcanic provinces exhibit a mean heat flow of about 80 mW/m² (Pollack et al. Reference Pollack, Hurter and Johnson1993), leading to a geothermal gradient commonly estimated at ∼25°C/km in the shallow parts of the Earth. But in volcanic terrains where magma may rest in the crust at temperatures of up to ∼1300°C, heat flow can locally exceed 30 W/m² and the geotherm may be a thousand times higher (see below, and Eichelberger et al. Reference Eichelberger, Carrigan, Ingolfsson, Lavallée, Ludden, Markússon, Sigmundsson and Consortium2021). Considering the heat capacity of magma, one can estimate that cooling 1 litre of magma from 1000°C to 20°C in 1 second, would generate approximately 1 MW; scaled up, a 1 km³ magma body could generate 1 GW_t for about 30 years (Eichelberger et al. Reference Eichelberger, Carrigan, Ingolfsson, Lavallée, Ludden, Markússon, Sigmundsson and Consortium2021). So, even small magmatic intrusions create considerable thermal anomalies (Burchardt et al. Reference Burchardt, Bazargan, Gestsson, Hieronymus, Ronchin, Tuffen, Heap, Davidson, Kennedy and Hobé2022). Yet, magma reservoirs can be hundreds and even thousands of cubic kilometres in volume, so the energy potential of magma is immense. Moreover, the rock surrounding magmatic bodies tends to be ‘wet’, hosting large-capacity hydrothermal systems which make harnessing fluids relatively simple, in comparison to tight, ‘dry’ rocks which require more extensive stimulation (i.e., enhanced geothermal systems, EGS). The hydrous nature of magma-geothermal systems provides a net advantage to the extraction of energy.

Heat retained in the Earth’s interior has long been exploited by humans and animals alike (Arriaga Reference Arriaga2005; Fraser et al. Reference Fraser, Terauds, Smellie, Convey and Chown2014). Utilized where readily available in active magmatic provinces for space heating since early civilization, efforts have most recently expanded to include the production of electricity by adapting technology from hydropower plants. As of 2022, geothermal energy accounts for ∼0.5% of our energy portfolio (IRENA and International Geothermal Association 2023). Largely this is due to the high production costs (compared with other energy sources) and heterogeneous worldwide distribution. Yet, in volcanic provinces, it can be the backbone of an energy supply and a strong economy. It has been estimated that 39 countries could produce 100% of their electricity with geothermal energy (Dauncey and Mazza Reference Dauncey and Mazza2001). In Iceland, geothermal energy is readily accessible and has been rooted in the lifestyle since Iceland’s early settlement, fostering its economic growth. In 2022, the country produced about 6 TWh of geothermal energy (i.e., 30% of its annual production) and over 90% of houses and many industries (aluminium smelting, cosmetics, geothermal spas) were powered by this renewable resource (Statistica 2021). This volcanic island hosts eight geothermal power plants and several hundred geothermal wells (commonly reaching ∼1–2 km in the Earth’s crust), generating an average of 5 MWh. In search of solutions to enhance the economics of geothermal resources by increasing energy output at a lower cost, a consortium between three Icelandic geothermal companies and academic experts was created in the year 2000 to establish the Iceland Deep Drilling Project (IDDP); their goal, to drill deeper in geothermal systems to reach hydrothermal fluids with higher enthalpy (i.e., energy density extant at supercritical conditions) to increase energy output. The first well (IDDP-1) was drilled in 2009 at Krafla volcano, which hosts a geothermal powerplant (with a capacity of 60 MW_e) operated by Landsvirkjun National Power Company of Iceland since 1978 (LV-2015-040). This site was chosen for the first borehole as extensive studies since the 1975–1984 Krafla Fires eruption had inferred the presence of a large magma reservoir at ∼5 km depth; hence IDDP-1 aimed to reach 4.5 km depth (Friðleifsson et al. Reference Friðleifsson, Ármannsson, Guðmundsson, Árnason, Mortensen, Pálsson and Einarsson2014). But to the astonishment of all, drilling had to cease at a mere 2.1 km, where they serendipitously encountered magma at a location not anticipated from geophysical surveys. This prompted operations to shift laterally, whereby magma was intersected a further two times. Hence, the consortium opted to perform flow tests which extracted fluids at a temperature of 450°C (Axelsson et al. Reference Axelsson, Egilson and Gylfadóttir2014); the hottest fluids ever recorded at a geothermal power plant. Although these fluids were corrosive and generated infrastructural challenges, the flow tests indicated that this magma well could potentially produce 36 MW_e (Axelsson et al. Reference Axelsson, Egilson and Gylfadóttir2014) that is, 5–10 times the average energy output of conventional wells in Iceland. Thus, in the right environment, a power station could rely on fewer wells to meet demand, significantly reducing operation and maintenance costs.

Lessons Learnt from Magma Encounters

Crucial lessons have been learnt from encountering magma at Krafla, and elsewhere. Here we review six of these, which must be studied and reflected upon as we plan future efforts.

(5) The Rocks Above Magma were Unexpectedly Highly Permeable to Fluids

In the geothermal sector, there is a common presumption that hot rocks are ductile and deform plastically, and so cannot fracture; therefore, it is assumed that fluid circulation cannot be efficient due to the lack of fracture pathways in near-magma environments. Yet during IDDP-1, drilling operations were disturbed at depths below 2000 m as the rocks became increasingly permeable, resulting in complete loss of the drilling fluids (15–45 L/s) to the surrounding rock (Mortensen et al. Reference Mortensen, Egilson, Gautason, Arnadottir and Guðmundsson2014).

Thermal stimulation is commonly practised to enhance fluid circulation in geothermal reservoirs (Grant et al. Reference Grant, Clearwater, Quinão, Bixley and Le Brun2013) where thermal contraction by cooling can be sufficient to fracture rocks (Timoshenko and Goodier Reference Timoshenko and Goodier1970). In natural cases, thermal jointing is commonly observed in rocks crystallized from magmatic intrusions, causing columnar joints (Figure 2(A)). Novel laboratory experiments on Icelandic lava showed that 150°C of cooling from the solidus (temperature below which material is fully crystalline) is sufficient to induce fractures (Lamur et al. Reference Lamur, Lavallée, Iddon, Hornby, Kendrick, von Aulock and Wadsworth2018). When cooling by fluids is efficient and rapid, magma can also vitrify (Dingwell and Webb Reference Dingwell and Webb1990); thus, by thermally stimulating a magma reservoir it can thermally joint at higher temperatures and over greater volumes (Figure 2(B)). Because cooling-induced contraction acts to widen the generated fractures (Lamur et al. Reference Lamur, Lavallée, Iddon, Hornby, Kendrick, von Aulock and Wadsworth2018), cooling from greater temperatures can more drastically enhance fluid flow (e.g., Lavallée et al. Reference Lavallée, Lamur, Kendrick, Eggertsson, Weaver, Eichelberger, Papale, Sigmundsson, Dingwell and Markússon2019), allowing magma wells to produce up to 10 times more energy than conventional geothermal wells (Figure 3). Thus, magma and its superhot surroundings are the ideal environments to perform thermal stimulation and extract energy.

Figure 2. Thermal fracturing in magmatic environments. (A) Columnar jointed basalt near Vík, Iceland, showing the geometrical fracture patterns that develop due to cooling contraction of magma and lava bodies. (B) Sketch of fracture arrangement during natural (left) and anthropogenically stimulated (right) cooling of magma. The sketch shows that fractures can penetrate magma if cooling is sufficient, for example enhanced by drilling fluids. These fractures allow fluid circulation, which transfers mass and heat into the hydrothermal system.

Figure 3. Extent of fluid flow enhancement due to cooling joint propagation during thermal stimulation of conventional geothermal systems versus magmatic systems, which can yield up to 10× more energy.

Creating the First International Magma Observatory

Arguably, safe access to magma will transform our understanding of magmatic systems and volcanic hazards and propel us into the next generation of geothermal energy, which we name: magma energy.

Innovative requirements must be met to safely access magma. We need a robust plan, informed by carefully integrating scientific knowledge, cutting-edge technologies and the latest engineering practices, in order to develop innovative magma engineering practices to successfully achieve this ambitious goal. Our knowledge is ripe for this vision.

The quest to access magma has been extensive. In addition to the above examples of unintentional magma drilling at Krafla, Puna and Menengai, we have a wealth of knowledge from pioneering coring into lava lakes in Hawaii by the US Geological Survey in the 1960s, which can be considered a prototype of future magma drilling. Most notable among these is Kilauea Iki lava lake (see Helz Reference Helz2009; Helz and Thornber Reference Helz and Thornber1987), which filled a crater by more than 100 m during the 1959 eruption of Kilauea. Kilauea Iki was cored multiple times over a period of more than two decades (achieving nearly 100% recovery), yielding a rich dataset including the liquid line of descent (i.e., tracking the evolution of mineral phases in time, space, and temperature), as well as constraints on heat transfer mechanisms (Hardee Reference Hardee1980) and processes of melt-crystal segregation. The knowledge obtained from these detailed studies forms the basis for all geoscience study programmes worldwide. In the late 1970s and early 1980s, the USGS was joined by Sandia National Laboratories as part of the US Department of Energy’s Magma Energy Project to test the feasibility of extracting energy directly from magma (see Colp Reference Colp1982), and included placing a heat exchanger directly into the molten lens below the surface of the solidifying lava lake. The project was judged to have demonstrated the feasibility of extracting energy directly from magma (Dunn et al. Reference Dunn, Ortega, Hickox, Chu, Wemple and Boehm1987), and has since paved the way for the future creation of the first magma observatory.

The creation of a magma observatory stands to transform current knowledge and provide new strategies for interpreting and utilizing the Earth as we enter the third millennium. To ensure applicability to other magmatic systems worldwide, a series of objectives need to be achieved. The activities should:

1. (1) Enable sampling, instrumentation and experimental manipulation of magma;

2. (2) Characterize the state and evolution of the magma-rock-hydrothermal transition zone to an unprecedented level;

3. (3) Develop new monitoring methods and approaches capable of identifying, locating, and characterizing magma bodies;

4. (4) Develop and test new designs to construct stable wells for sampling and continuous long-term monitoring of magma bodies;

5. (5) Test new materials and instruments resilient to extreme conditions;

6. (6) Develop and test new energy harnessing technologies;

7. (7) Evaluate the response of magma and fluids to geothermal exploration and utilization.

8. (8) Develop guidelines to assess magma response to drilling to inform operations in real-time; and

9. (9) Improve reliability of warnings of impending volcanic eruptions worldwide through a ground-truthed understanding of subsurface volcanic processes and how to monitor and interpret them.

Such fundamental goals must be at the core of a magma observatory. With these in mind, and equipped with the knowledge that previous drilling efforts in lava lakes and magmas have provided unparalleled insights into magma dynamics, an international initiative was created between academics and the industry to establish the first magma observatory, under the auspices of the Krafla Magma Testbed (KMT; www.kmt.is). The vision of KMT is to become a world-class international in situ magma laboratory with access to the magma-rock-hydrothermal boundary through wells, available for advanced studies and experiments. Endorsed by the government of Iceland and supported by the International Continental Scientific Drilling Program (ICDP) the project has gained momentum since its inception in September 2014 and meticulous interdisciplinary planning resulted in the creation of a non-profit organization in autumn 2023.

The KMT infrastructure will include a multi-hole facility and an education centre to foster scientific exchange and knowledge transfer to the next generations, the public, stakeholders, and authorities. A range of innovative activities have been planned for the next few decades. In the first instance, two wells will be produced, whilst monitoring the system using surface, downhole and space-borne instruments (Figure 4).

• • Well 1 will enable sampling across the rock–magma interface to characterize the state of this transition and the properties and conditions of magma. Subsequently, well 1 will be instrumented with thermocouples, fibre-optic cables, and strain gauges, to monitor the temperature, pressure, and deformation of the rock and magma. Once completed, the system will be allowed to thermally relax (to reach its ‘background’ conditions following the disturbance prompted by drilling and fluid injection), thus enabling constraints on the extent of disturbance by drilling and on the ambient condition of the magma-hydrothermal system. Experiments will be undertaken to quantify signal propagation in the rocks and magma, to refine models that interpret the subsurface.

• • Well 2 will enable experimentation. Well 2 will be drilled ∼1 year later, following complete relaxation of the system imparted by the operations in well 1. Close monitoring via instruments in well 1 will allow for a direct assessment of the response of magma to drilling well 2. Magma will be sampled to assess how the system evolved during that period. Following completion of the well, a range of experiments will be undertaken, including magma manipulation to assess the response of magma, thermo-mechanical stimulation followed by flow tests to assess the energy offered by magmatic fluids and to optimize future geothermal energy harnessing practices, and, finally, to test the resilience of new materials, sensors and instruments to extreme environments such as magma bodies, or near-magmatic environments extant in black smokers (increasingly considered for geothermal energy production), on other planets (e.g., Venus), and in certain industries (e.g., nuclear power plants, metallurgy, glass manufacturers).

Figure 4. Illustration of the implementation plan of the Krafla Magma Testbed. More information can be found at www.kmt.is.

Following the success of these two wells, further wells are planned for energy and complementary observations of the system.

A magma observatory is needed to bolster large-scale international scientific infrastructure (e.g., hadron collider, arctic station, international space station, etc.) and enhance the completeness of Earth system observations; to date, we have higher resolution images of the Sun’s surface than of our own planetary interior. The opportunity to obtain direct access to magma will transform the geosciences and our ability to engineer the Earth. One could even speculate that, in the future, in volcanology and geothermal science, we will refer to the time as before KMT and after KMT.

The vision of KMT is commendable and the prospect of accessing magma has recently gathered significant attention from the media, the public, and industry. In recent years, an increasing number of start-ups have developed their service strategy around the opportunity offered by magma energy. The world needs to hear about this prospect, to maximize the future use of this resource globally and improve our sustainability on Earth.

Empowering Cities on Magma

Active volcanoes are found in many settings around the globe (Figure 5). Many major cities and megalopolises are built on volcanic landscapes (Tokyo, Mexico City, Naples, Auckland, to name but a few). Reiterating that ∼10% of the Earth’s population live within 100 km of an active volcano, it is crucial that we begin exploring and utilizing the magmatic environment immediately. The potential global impact of accessing magma – both for volcanic hazards and magma energy – is vast (Figure 5), especially when considering that the majority of countries eligible to receive official development assistance (ODA) by the intergovernmental Organization for Economic Co-operation and Development, are volcanically and so magmatically active. Accessing magma could radically transform the economic landscape. In Europe alone, the economic potential offered by magma exploration is tremendous, as several countries are volcanically active (i.e., having had an eruption in the past 10,000 years; e.g., France, Iceland, Italy, Spain, Portugal, Greece) or have experienced relatively recent volcanic eruptions (Germany, Luxembourg), or are associated with volcanically active colonies and/or territories (e.g., Montserrat, Guadeloupe, Reunion Island, etc.). We must learn to access this resource safely to harness its tremendous power. Magma energy offers higher energy output at a reduced cost, which could radically revolutionize the performance of geothermal energy in the world energy landscape. Similarly, we stand to gain a wealth of information on volcanic unrest. Just as we all heavily rely on weather forecasting tools to go about our daily activities, it is now time for the volcanological community to modernize its approaches and ground-truth observations to develop a comprehensive quantitative model capable of predicting the lifecycle of magma (from its genesis to its differentiation, storage, transport, and eruption), to constrain the global impact of volcanic emissions to the atmosphere, the hydrosphere, the biosphere, and climate. Accessing magma, next-generation geothermal energy, and modernization of volcanology are direly needed for communities, stakeholders, policymakers and the industry to improve sustainability, increase our preparedness, and build a more resilient future.

Figure 5. Global distribution and coexistence of active volcanoes and geothermal power plants. Active volcanoes shown were compiled by the Smithsonian Institution © [https://volcano.si.edu/projects/vaac-data/] and are defined as those exhibiting activity in the last 10,000 years (Global Volcanism Program, 2023). Powerplants are defined as operational or planned/unverified (Coro and Trumpy Reference Coro and Trumpy2020). The map was constructed in MATLAB using a basemap provided by Esri (2009).