International teams of researchers, including two scientists from the University of Rochester, have been studying the location and behaviour of magma chambers on the Earth's mid-ocean ridge system—a vast chain of volcanoes along which the Earth forms new crust.
They worked in the tropical region of Afar, Ethiopia and the subarctic country of Iceland—the only places where mid-ocean ridges appear above sea level. Volcanic ridges (or "spreading centers") occur when tectonic plates "rift" or pull apart. This happens when magma (hot molten rock) injects itself into weaknesses in the brittle upper crust, erupting as lava and forming new crust upon cooling.
"These conclusions would not have been possible without the multi-disciplinary expertise of the researchers taking part in these studies," said Cynthia Ebinger, professor of geophysics at the University of Rochester.
The studies, published in Nature Geoscience, reveal new information about where magma is stored and how it moves through the geological plumbing network.
Magma chambers work like plumbing systems, channelling pressurized magma through networks of underground "pipes." Finding out where magma chambers lie and how they behave could help identify early warning signs of impending eruptions, according to the researchers.
By analyzing images taken by the European Space Agency satellite Envisat, scientists were able to measure how the ground moved before, during, and after eruptions. Also, Ebinger and Manahloh Belachew, also from the University of Rochester, operated an array of seismographs that provided the depth and detailed time control to gauge the fracturing of the earth and the flow of magma from multiple eruptions in Afar. Using these data, the international team built and tested computer models to find out how rifting occurs.
The team of scientists discovered that the ground started "uplifting" (elevating) four months before the eruption, due to new magma increasing pressure in one of the underground chambers. They hope the ground movement will prove to be precursory signals that are fundamental to predicting eruptions.
In an extensive study of eruptions in Afar and Iceland—two vastly different environments—Ebinger and Belachew found remarkable similarities, with many events occurring within a short space of time. They identified multiple magma chambers positioned horizontally and vertically, allowing magma to shoot in several directions. Earthquake patterns were used to track the migrating magma as it inflated cracks, and to map the rupture of faults above the miles of propagating magma injection zones. The combined data sets show that separate magma chambers fed single eruptions.
A sequence of eruptions in Afar from 2005 to the present is part of an unusual period of volcanic unrest in Ethiopia, and is enabling scientists to learn more about magma plumbing systems at spreading centers. Most spreading centers are about a mile under water at the bottom of the ocean, making detailed observations extremely challenging.
"Our studies in Ethiopia open the door to new discoveries of multi-tiered magma chambers along submerged mid-ocean ridges worldwide," said Ebinger. "We also found that magma movement and faulting during intense episodes create much of the characteristic rift valley topography, where narrow lowlands are found between mountain ranges."
When magma intrudes into a region it generates earthquakes, according to Belachew, a Ph.D. candidate. "The detailed relations of the earthquake sequences in both time and space allow us to track the movement of magma and associated fault rupture with unprecedented detail," he said.
Tim Wright, from the University of Leeds' School of Earth and Environment, heads the international Afar Rift Consortium. "The dramatic events we have been witnessing in Afar in the past six years are transforming our understanding of how the crust grows when tectonic plates pull apart," said Wright. "Our work in one of the hottest places on Earth is having a direct impact on our understanding of eruptions from the frozen volcanoes of Iceland."
The studies were funded by the UK Natural Environment Research Council through the Afar Rift Consortium, the National Centre for Earth Observation, the US National Science Foundation, the UK Royal Society, and the Icelandic Research Fund. Seismic instrumentation was provided by IRIS-PASSCAL and Seis-UK; GPS instrumentation by UNAVCO.
Peter Iglinski | EurekAlert!
Artificial light in the Arctic
08.04.2020 | University of Delaware
Most of Earth's carbon was hidden in the core during its formative years
02.04.2020 | Smithsonian
Published by Marc Tudela, Laura Becerra-Fajardo, Aracelys García-Moreno, Jesus Minguillon and Antoni Ivorra, in Access, the journal of the Institute of Electrical and Electronics Engineers
The project Electronic AXONs: wireless microstimulators based on electronic rectification of epidermically applied currents (eAXON, 2017-2022), funded by a...
The Belle II experiment has been collecting data from physical measurements for about one year. After several years of rebuilding work, both the SuperKEKB electron–positron accelerator and the Belle II detector have been improved compared with their predecessors in order to achieve a 40-fold higher data rate.
Scientists at 12 institutes in Germany are involved in constructing and operating the detector, developing evaluation algorithms, and analyzing the data.
Electrolytes play a key role in many areas: They are crucial for the storage of energy in our body as well as in batteries. In order to release energy, ions - charged atoms - must move in a liquid such as water. Until now the precise mechanism by which they move through the atoms and molecules of the electrolyte has, however, remained largely unknown. Scientists at the Max Planck Institute for Polymer Research have now shown that the electrical resistance of an electrolyte, which is determined by the motion of ions, can be traced back to microscopic vibrations of these dissolved ions.
In chemistry, common table salt is also known as sodium chloride. If this salt is dissolved in water, sodium and chloride atoms dissolve as positively or...
Drops of water falling on or sliding over surfaces may leave behind traces of electrical charge, causing the drops to charge themselves. Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz have now begun a detailed investigation into this phenomenon that accompanies us in every-day life. They developed a method to quantify the charge generation and additionally created a theoretical model to aid understanding. According to the scientists, the observed effect could be a source of generated power and an important building block for understanding frictional electricity.
Water drops sliding over non-conducting surfaces can be found everywhere in our lives: From the dripping of a coffee machine, to a rinse in the shower, to an...
90 million-year-old forest soil provides unexpected evidence for exceptionally warm climate near the South Pole in the Cretaceous
An international team of researchers led by geoscientists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) have now...
07.04.2020 | Event News
06.04.2020 | Event News
02.04.2020 | Event News
08.04.2020 | Physics and Astronomy
08.04.2020 | Information Technology
08.04.2020 | Medical Engineering