About how dedicated superizverzheniyam master thesis Novosibirsk student grew into a full article in the prestigious scientific journal Science, said the science department “Gazety.Ru».
Master’s thesis student at Novosibirsk State University Kayrly Dzhaksybulatova eventually graduated to full article in the prestigious scientific journal Science. Its results “Times” interviewed co-author articles, head of the Laboratory of seismic tomography of the Institute of Petroleum Geology and Geophysics. AA Trofimuk Siberian Branch of RAS (IPGG SB RAS), Doctor of Geological and Mineralogical Sciences Ivan Kulakov.
– What is in your work?
– Caldera Toba – this place is the biggest in the last few million years of the eruption, which occurred 74 thousand. Years ago and led to the release of about 2,800 cubic meters. km species. Superizverzheny problem is one of the hottest in the Earth sciences.
Among the specialists actively discussed the question of how such a number of magmatic material could accumulate under the volcano.
Based on the results of the seismic survey, the crust at depths greater than 7 km is strongly anisotropic, indicating a pronounced layered structure in which alternate with horizontal bedrock towards the introduction of magmatic material. This confirms the assumption of other authors, who believe that the layered structure of the magma chamber is only possible under the supervolcano. In the upper crust directly beneath the caldera Toba anomaly with reduced seismic velocities and isotropic properties, which may coincide with the position of the huge crater depth of 5-7 km, resulting in an explosion of 70 thousand. Years ago.
– What are the methods used in this case? What is your contribution directly?
– The paper used a relatively new method of noise tomography, which was proposed several years ago by our co-author Nicholas Shapiro, and which has already gained popularity in many scientific centers of the world. This method is useful in the selection of seismic waves from the continuous recording of natural sound, with which you can explore the deep structure of the Earth.
A new feature of this work is the use of surface waves of two types, Rayleigh and Love, which allow to study separately the elastic properties in the vertical and horizontal directions. Based on the difference of seismic velocities obtained using these waves, we can conclude about the anisotropy of the Earth’s crust.
The main calculations were performed by the first author Kayrly Dzhaksybulatovym who began this work as undergraduates NSU and laboratory workers seismic tomography IPGG SB RAS. Ivan Kulakov has previously had experience with this supervolcano. In this work, he was actively involved in the geological interpretation of the results. Nicholas Shapiro – our countryman; currently works at the Institute of Physics of the Earth in Paris (IPGP).
That he suggested the use of surface waves to detect different types of radial anisotropy in the world.
– As the conclusions of the article will help geologists?
– A new method of analysis of seismic data proved to be extremely effective for the detection of seismic anisotropy in the crust. It is supposed to apply it in other areas of potential superizverzheny and assess the risk of such events.
– Where surveys conducted? Does your institution or Russian work was only abroad?
– Question superizverzheny has global importance.
If this scale eruption happened in the moment, it would change the life of mankind and all species on Earth. Therefore, on this issue are specialists from different countries.
In this paper, in addition to Russian scientists were involved experts from France and Germany, which have created algorithms and helped with their practical implementation for data Toba caldera. In addition, this work would not be possible without a network of seismic stations installed in the caldera forces Institute GFZ Potsdam. Calculations were carried out mainly in the Paris Institute of Physics of the Earth, where Kayrly Dzhaksybulatov was sent for training.
– What is the likelihood that superizverzhenie happen in our time?
– This is a problem that is seriously engaged scientists. 70 thousand. Years in geological terms – this instant. In the time that has passed since the eruption on Tobe, no fundamental changes in the world had happened.
Thus, the probability of such an event is now no less than 100 thousand. or 1 million years ago. Another thing that is a major event occur suddenly can hardly.
If the crust rearrangement and accumulation of huge masses of high pressure, it must surely lead to some indirect events such as earthquakes or earth surface displacements, which in the modern development of geophysical monitoring is impossible to miss. In the event of a major eruption precursors begin to appear and grow in intensity for months or even years before the main collapse.
In my opinion, the preparation superizverzheniya will be much longer. Nothing like this anywhere else now we do not see; so that we can be relatively calm.
Recent examples – Taupo eruption in New Zealand about 26 thousand. years ago. By volume compares with You, but had significantly less impact on the biosphere. From human history – Tambora in Indonesia in 1815, after which in Europe and America was pestilence livestock and people from the cold and hunger; in Germany in the summer of snow lying. The volume of the eruption – “only” 160 cu. km.
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