Analysis of seismograms from more than 700 stations allowed the identification of a layer of partially molten material in the upper mantle, a finding that could help to better understand volcanoes and terrestrial earthquakes.
movement of tectonic plates The huge slabs of rock that lie beneath the oceans and continents, dividing the earth and generating great earthquakes, are one of the aspects of greatest interest to geologists. Now, a team of researchers has discovered a new layer of partially molten material that lies beneath Earth’s crust just below those tectonic plates, as detailed in an investigation published this Monday in the journal . Nature Geology.
Scientists have previously identified patches of molten material at similar depths, but this new study led by the University of Texas at Austin (USA) reveals for the first time the global extent of this layer, which is about 100 miles across. located at depth. relative to the Earth’s surface and part of the callasthenosphereWhich is the upper region of the Earth’s mantle.
“Its importance in the asthenosphere and the movement of lithospheric plates has been known for decades, but this new work precisely identifies a partially molten global low-velocity region at the base of the asthenosphere, which confirms and adds to this importance.” does” the reality of some theoretical models “that, until now, were purely speculative on the subject,” explains Jesús Martínez-Frais, a planetary geologist at the Institute of Geosciences (IGEO/CSIC-UCM), who was involved in the study Not there.
The idea to search for a new layer in Earth’s interior came to Junlin Hua, a postdoctoral fellow in UT’s Jackson School of Geosciences and leader of the research, when he studied seismic images beneath Turkey during his doctoral research. Intrigued by signs of partially molten rock beneath the crust, he collected similar images from other seismic stations until he had a global map of the asthenosphere. What he and others had taken to be an anomaly was, in fact, common around the world, with seismic readings showing where the asthenosphere was hottest.
“This work is important because understanding the properties of the asthenosphere is key to understanding plate tectonics,” said Karen Fischer, a seismologist and professor at Brown University and co-author of the research.
Seismogram of 716 stations
As Martínez-Fries explains, research into the Earth’s interior is a really complex problem: “In this excellent research they have been able to study and analyze seismograms from 716 stations and apply different computerized and probabilistic models in a coordinated way.” do, try to establish not only the depth at which it is found, but also its global nature. In my opinion, this is also an important investigation from a compositional, petrological and geochemical point of view, because The asthenosphere is primarily composed of silicates, particularly olivine and pyroxene., Therefore, this study will also have an indirect impact on the characterization of some igneous processes and types of eruptions”, commented the head of the CSIC Research Group on Meteorites and Planetary Geology.
Spanish scientists insist that “Earth is a geologically living planet, geologically active. This study is not only very relevant to describe and better understand the relationship between the crust and the upper mantle, but it can complement models of the link between seismology and the dynamics of volcanoes and plate tectonics. In my opinion, this opens a door for geological review and better characterization of “local regions” where both earthquakes and volcanic activity occur in a linked manner and for specifying more concrete geological models on the Earth’s interior, and, as an extrapolation, to other terrestrial-type planets, such as Venus or Mars”.
