From Imperial College London (UK) : “Magma observed taking an unexpected route beneath volcanoes”

From Imperial College London (UK)

2.6.23
Caroline Brogan

Mauna Loa Volcano. Credit: USGS

Imperial researchers have observed magma taking an unexpected route beneath volcanoes, shedding light on the processes behind eruptions.

The findings [Science Advances (below)] were based on data from a tectonic plate boundary in the Eastern Caribbean region. The results help us understand what drives the type and rate of volcanic eruptions, as well as the make-up of erupted magma. They could also help us understand why some volcanoes are more active than others, and why volcanic activity changes over time.

Fig. 1. Seismotectonic context of the Lesser Antilles arc, with S-wave ray-path coverage and path-averaged t*S results.
The red box on the inset map shows the extent of the main map. Island names are labeled in italic; tectonic features are in bold. Ray-paths in the map (top) and cross-sectional view (bottom) are traced in a three-dimensional (3D) velocity model (42), with ray-path colors showing the path-averaged attenuation operator (t*pathave). Orange paths have strong attenuation; green paths have weak attenuation. The orientation of the 2D model spanning the northern LAA shown in Fig. 2 is given by the red dashed line labeled X-X′. On the cross-sectional view, representative 8-s-long S waveforms on thetransverse component are given for back-arc ray-paths (orange) and a fore-arc path (green) from the same intraslab earthquake at 180 km in depth (details in fig. S1).

When two huge tectonic plates collide, one plate can sink, or subduct, beneath the other, plunging into Earth’s mantle to release water and melt. As the plates rub together and the melted material rises to form magma, these subduction zones are responsible for some of Earth’s most hazardous earthquakes and explosive volcanic eruptions.

However, it remains poorly understood how magma forms underground and what controls the exact position of volcanoes on top of the overlying plate.

Now, a new study published in Science Advances [below] shows how rising magma, which eventually erupts, does not always take the shortest, most direct path available to reach volcanoes at the surface.

Lead author Dr Stephen Hicks, who undertook the work at Imperial’s Department of Earth Science and Engineering and now works at UCL, said: “Scientific views in this much-debated subject have traditionally fallen into two tribes. Some believe the subducting plate mostly controls where the volcanoes are, and some think the overlying plate plays the biggest role. But in our study, we show that the interplay of these two driving forces over hundreds of millions of years is key to controlling where eruptions occur today.”

Under pressure

Subducting oceanic plates act as giant reservoirs, transporting water into the deep Earth. These fluids enter the plate through fractures and faults formed during its birth and where it later bends beneath Earth’s deep ocean trenches. Water gets locked into fractures and bound into minerals within the plate.

Subducting plates are subjected to high pressures and temperatures as they plunge to between ten and 100 kilometres deep. These extreme conditions cause the locked-in water, and other volatile elements, to be driven off. These fluids, which melt the warm mantle above, are the key ingredient of magma that eventually erupts around arcs of volcanoes at the edges of Earth’s oceans, such as the Pacific Ring of Fire.

Ring of Fire Credit National Geographics.

Yet the pathways that fluids and melt take deep within the Earth, from the subducting plate to the volcanic arc, cannot be directly seen nor easily inferred from what is erupted.

To carry out the study, the researchers used earthquake data to map seismic absorption in 3D, similar to how a CT scan maps the internal structure of our bodies. When seismic energy from earthquakes travels through different materials, the waves either slow down or speed up. Along with these speed changes, the energy of waves also dissipates. Hot and molten rock is particularly attenuating: it zaps energy from seismic waves as they travel through it.

The team collected seismic data from a subduction zone in the Eastern Caribbean that resulted in the Lesser Antilles’ volcanic islands, by using ocean-bottom seismometers to build an accurate 3D picture of the subsurface.

Unusually, the study found that the zone of strongest seismic attenuation at depth was offset sideways from beneath the volcanoes. These images led the authors to conclude that once water is expelled from the subducting plate, it is carried further downwards, leading to mantle melting behind the volcanic front. Melt then pools at the base of the overriding plate before it is likely transported back toward the volcanic arc.

The researchers used earthquake data to map seismic absorption in 3D, similar to how a CT scan maps our bodies.

Study co-author Professor Saskia Goes, also of the Department of Earth Science and Engineering at Imperial, said: “Our knowledge of fluid and melt pathways has traditionally been focussed on subduction zones around the Pacific. We decided to study the subduction of the Atlantic instead because the oceanic plate there was formed much more slowly, accompanied by more faulting, and it subducts more slowly than in the Pacific. We felt these more extreme conditions would make fluid and melt pathways more imageable using seismic waves.

“Our findings give us important clues about the processes behind volcanic eruptions, and could help us to better understand where the magma reservoirs below volcanoes get formed and replenished.”

The published paper results from an international collaboration between scientists from the United Kingdom, the United States, Germany, and Trinidad.

The study was funded by the Natural Environment Research Council (NERC), part of UKRI – UK Research and Innovation(UK)

Science Advances
See the science paper for instructive material with images.

See the full article here.

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Imperial College London (UK) is a science-based university with an international reputation for excellence in teaching and research. Consistently rated amongst the world’s best universities, Imperial is committed to developing the next generation of researchers, scientists and academics through collaboration across disciplines. Located in the heart of London, Imperial is a multidisciplinary space for education, research, translation and commercialization, harnessing science and innovation to tackle global challenges.

Imperial College London (legally Imperial College of Science, Technology and Medicine) is a public research university in London. Imperial grew out of Prince Albert’s vision of an area for culture, including the Royal Albert Hall; Imperial Institute; numerous museums and the Royal Colleges that would go on to form the college. In 1907, Imperial College was established by Royal Charter, merging the Royal College of Science; Royal School of Mines; and City and Guilds College. In 1988, the Imperial College School of Medicine was formed by combining with St Mary’s Hospital Medical School. In 2004, Queen Elizabeth II opened the Imperial College Business School.

The college focuses exclusively on science; technology; medicine; and business. The college’s main campus is located in South Kensington, and it has an innovation campus in White City; a research field station at Silwood Park; and teaching hospitals throughout London. The college was a member of the University of London(UK) from 1908, becoming independent on its centenary in 2007. Imperial has an international community, with more than 59% of students from outside the UK and 140 countries represented on campus. Student, staff, and researcher affiliations include 14 Nobel laureates; 3 Fields Medalists; 2 Breakthrough Prize winners; 1 Turing Award winner; 74 Fellows of the Royal Society; 87 Fellows of the Royal Academy of Engineering; and 85 Fellows of the Academy of Medical Sciences.

History

19th century

The earliest college that led to the formation of Imperial was the Royal College of Chemistry founded in 1845 with the support of Prince Albert and parliament. This was merged in 1853 into what became known as the Royal School of Mines. The medical school has roots in many different schools across London, the oldest of which being Charing Cross Hospital Medical School which can be traced back to 1823 followed by teaching starting at Westminster Hospital in 1834 and St Mary’s Hospital in 1851.

In 1851 the Great Exhibition was organized as an exhibition of culture and industry by Henry Cole and by Prince Albert- husband of the reigning monarch of the United Kingdom Queen Victoria. An enormously popular and financial success proceeds from the Great Exhibition were designated to develop an area for cultural and scientific advancement in South Kensington. Within the next 6 years the Victoria and Albert Museum and Science Museum had opened joined by new facilities in 1871 for the Royal College of Chemistry and in 1881 for the Royal School of Mines; the opening of the Natural History Museum in 1881; and in 1888 the Imperial Institute.

In 1881 the Normal School of Science was established in South Kensington under the leadership of Thomas Huxley taking over responsibility for the teaching of the natural sciences and agriculture from the Royal School of Mines. The school was renamed the Royal College of Science by royal consent in 1890. The Central Institution of the City and Guilds of London Institute was opened as a technical education school on Exhibition Road by the Prince of Wales in early 1885.

20th century

At the start of the 20th century, there was a concern that Britain was falling behind Germany in scientific and technical education. A departmental committee was set up at the Board of Education in 1904, to look into the future of the Royal College of Science. A report released in 1906 called for the establishment of an institution unifying the Royal College of Science and the Royal School of Mines, as well as – if an agreement could be reached with the City and Guilds of London Institute – their Central Technical College.

On 8 July 1907 King Edward VII granted a Royal Charter establishing the Imperial College of Science and Technology. This incorporated the Royal School of Mines and the Royal College of Science. It also made provisions for the City and Guilds College to join once conditions regarding its governance were met as well as for Imperial to become a college of The University of London. The college joined the University of London on 22 July 1908 with the City and Guilds College joining in 1910. The main campus of Imperial College was constructed beside the buildings of the Imperial Institute- the new building for the Royal College of Science having opened across from it in 1906 and the foundation stone for the Royal School of Mines building being laid by King Edward VII in July 1909.

As students at Imperial had to study separately for London degrees in January 1919 students and alumni voted for a petition to make Imperial a university with its own degree awarding powers independent of the University of London. In response the University of London changed its regulations in 1925 so that the courses taught only at Imperial would be examined by the university enabling students to gain a BSc.

In October 1945 King George VI and Queen Elizabeth visited Imperial to commemorate the centenary of the Royal College of Chemistry which was the oldest of the institutions that united to form Imperial College. “Commemoration Day” named after this visit is held every October as the university’s main graduation ceremony. The college also acquired a biology field station at Silwood Park near Ascot, Berkshire in 1947.

Following the Second World War, there was again concern that Britain was falling behind in science – this time to the United States. The Percy Report of 1945 and Barlow Committee in 1946 called for a “British MIT”-equivalent backed by influential scientists as politicians of the time including Lord Cherwell; Sir Lawrence Bragg; and Sir Edward Appleton. The University Grants Committee strongly opposed however. So, a compromise was reached in 1953 where Imperial would remain within the university but double in size over the next ten years. The expansion led to a number of new buildings being erected. These included the Hill building in 1957 and the Physics building in 1960 and the completion of the East Quadrangle built in four stages between 1959 and 1965. The building work also meant the demolition of the City and Guilds College building in 1962–63 and the Imperial Institute’s building by 1967. Opposition from the Royal Fine Arts Commission and others meant that Queen’s Tower was retained with work carried out between 1966 and 1968 to make it free standing. New laboratories for biochemistry established with the support of a £350,000 grant from the Wolfson Foundation were opened by the Queen in 1965.

In 1988 Imperial merged with St Mary’s Hospital Medical School under the Imperial College Act 1988. Amendments to the royal charter changed the formal name of the institution to The Imperial College of Science Technology and Medicine and made St Mary’s a constituent college. This was followed by mergers with the National Heart and Lung Institute in 1995 and the Charing Cross and Westminster Medical School; Royal Postgraduate Medical School; and the Institute of Obstetrics and Gynecology in 1997 with the Imperial College Act 1997 formally establishing the Imperial College School of Medicine.

21st century

In 2003, Imperial was granted degree-awarding powers in its own right by the Privy Council. In 2004, the Imperial College Business School and a new main entrance on Exhibition Road were opened by Queen Elizabeth II. The UK Energy Research Centre was also established in 2004 and opened its headquarters at Imperial. On 9 December 2005, Imperial announced that it would commence negotiations to secede from the University of London. Imperial became fully independent of the University of London in July 2007.

In April 2011 Imperial and King’s College London joined the UK Centre for Medical Research and Innovation as partners with a commitment of £40 million each to the project. The centre was later renamed The Francis Crick Institute (UK) and opened on 9 November 2016. It is the largest single biomedical laboratory in Europe. The college began moving into the new White City campus in 2016 with the launching of the Innovation Hub. This was followed by the opening of the Molecular Sciences Research Hub for the Department of Chemistry officially opened by Mayor of London- Sadiq Khan in 2019. The White City campus also includes another biomedical centre funded by a £40 million donation by alumnus Sir Michael Uren.

Research

Imperial submitted a total of 1,257 staff across 14 units of assessment to the 2014 Research Excellence Framework (REF) assessment. This found that 91% of Imperial’s research is “world-leading” (46% achieved the highest possible 4* score) or “internationally excellent” (44% achieved 3*) giving an overall GPA of 3.36. In rankings produced by Times Higher Education based upon the REF results Imperial was ranked 2nd overall. Imperial is also widely known to have been a critical contributor of the discovery of penicillin; the invention of fiber optics; and the development of holography. The college promotes research commercialization partly through its dedicated technology transfer company- Imperial Innovations- which has given rise to a large number of spin-out companies based on academic research. Imperial College has a long-term partnership with the Massachusetts Institute of Technology that dates back from World War II. The United States is the college’s top collaborating foreign country with more than 15,000 articles co-authored by Imperial and U.S.-based authors over the last 10 years.

In January 2018 the mathematics department of Imperial and the CNRS-The National Center for Scientific Research[Centre national de la recherche scientifique](FR) launched UMI Abraham de Moivre at Imperial- a joint research laboratory of mathematics focused on unsolved problems and bridging British and French scientific communities. The Fields medallists Cédric Villani and Martin Hairer hosted the launch presentation. The CNRS-Imperial partnership started a joint PhD program in mathematics and further expanded in June 2020 to include other departments. In October 2018, Imperial College launched the Imperial Cancer Research UK Center- a research collaboration that aims to find innovative ways to improve the precision of cancer treatments inaugurated by former Vice President of the United States Joe Biden as part of his Biden Cancer Initiative.

Imperial was one of the ten leading contributors to the National Aeronautics and Space Administration InSight Mars lander which landed on planet Mars in November 2018, with the college logo appearing on the craft. InSight’s Seismic Experiment for Interior Structure, developed at Imperial, measured the first likely marsquake reading in April 2019. In 2019 it was revealed that the Blackett Laboratory would be constructing an instrument for the European Space (EU) Solar Orbiter in a mission to study the Sun, which launched in February 2020. The laboratory is also designing part of the DUNE/LBNF Deep Underground Neutrino Experiment.

In early 2020 immunology research at the Faculty of Medicine focused on SARS-CoV-2 under the leadership of Professor Robin Shattock as part of the college’s COVID-19 Response Team including the search of a cheap vaccine which started human trials on 15 June 2020. Professor Neil Ferguson’s 16 March report entitled Impact of non-pharmaceutical interventions (NPIs) to reduce COVID- 19 mortality and healthcare demand was described in a 17 March The New York Times article as the coronavirus “report that jarred the U.S. and the U.K. to action”. Since 18 May 2020 Imperial College’s Dr. Samir Bhatt has been advising the state of New York for its reopening plan. Governor of New York Andrew Cuomo said that “the Imperial College model- as we’ve been following this for weeks- was the best most accurate model.” The hospitals from the Imperial College Healthcare NHS Trust which have been caring for COVID-19 infected patients partnered with Microsoft to use their HoloLens when treating those patients reducing the amount of time spent by staff in high-risk areas by up to 83% as well as saving up to 700 items of PPE per ward, per week.