Them. A. A. Trofimuk SB RAS explores the fire-breathing mountains of Kamchatka. Ahead is a major international project with the intriguing name KISS, designed to reveal the phenomenon of the mysterious Klyuchevskaya group of volcanoes, which has no analogues in the world.
“The study of processes inside volcanoes is a kind of “thriller”. If in other geological objects changes occur on time scales of millions or even billions of years, here everything can change extremely quickly - within a year, month or even days. By using modern methods geophysicists can observe the processes occurring under the volcano in real time, which is an extremely exciting task, the solution of which will not be boring,” says the head of the seismic tomography laboratory, Doctor of Geological and Mineralogical Sciences Ivan Yurievich Kulakov.
Expeditionary activities started 3 years ago. Previously, scientists had to work with data provided by colleagues from other countries on various volcanoes around the world, located in Indonesia, South America and other places. The first expedition season in 2012, Siberian researchers began with a relatively simple task - they set up a network of 11 stations (in addition to 7 local ones) on the volcanoes of the Avachinskaya group, which residents of Petropavlovsk-Kamchatsky call “home”, since they are located in close proximity from the city.
Here, geologists faced a serious problem: the volcanoes, which had previously been seismically active, suddenly became quiet after the installation of the stations, and it was not possible to collect the required amount of information on earthquakes. Moreover, due to severe frosts Batteries began to fail, causing some stations to shut down earlier than planned. Scientists were helped by a relatively new method of noise tomography (proposed by our compatriot from Paris Nikolai Shapiro), which allows one to isolate useful seismic waves from the analysis of continuous recordings of natural noise. Thanks to him, he was able to construct a three-dimensional seismic model of the subsurface beneath the Avachinsky and Koryaksky volcanoes. So, it turned out that the first one is located on the edge of a large low-velocity anomaly, which, apparently, is a trace of a caldera formed as a result of a huge explosion 35-40 thousand years ago and subsequently filled with eruption products of Avacha Sopka. This is important information for geology, indicating the serious explosive potential of volcanoes located in the immediate vicinity of Petropavlovsk-Kamchatsky.
The seismic station includes a sensor - a sensitive microphone that measures vibrations occurring in the ground in a very wide frequency range from hundreds of hertz to periods of tens and even hundreds of seconds. Using the recorder, they are converted into digital form and recorded on a regular memory card. Using these seismograms, geophysicists measure the “pulse of the earth” and study the deep structure of the subsoil. Currently, Novosibirsk residents have at their disposal a network of twenty stations, which are buried for one year; every season - on a new volcano. During this time, the equipment operates autonomously; data can be analyzed only after the devices are removed.
Since the accumulation of energy inside an active volcano occurs gradually, it is even useful for it to “discharge” from time to time. In this regard, Avachinskaya Sopka, located close to Petropavlovsk-Kamchatsky, most likely does not pose a particular danger to the city due to fairly regular eruptions of moderate power. The neighboring Koryaksky volcano is of much greater concern - it has an almost ideal shape, indicating the absence of explosions in the recent geological past. At the same time, gas emissions periodically occur there and seismic activity is observed. “It is to this that Kamchatka volcanologists today should pay the closest attention,” says Ivan Yurievich.
In 2013, the object of research by Novosibirsk scientists was the Gorely volcano, located 70 km from Petropavlovsk. It does not have such a beautiful cone as many other Kamchatka volcanoes, but it is interesting from the point of view of geology and modern activity. First of all, because it is located in the center of a caldera with a diameter of about 20 km, formed approximately 33.6 thousand years ago as a result of an eruption during which about 100 cubic meters were thrown into the air. km of rocks. “If this happened somewhere on Earth today, it would have a significant impact on the life of all humanity, and most modern problems would fade into the background against the backdrop of air pollution and climate change caused by the eruption,” notes Ivan Kulakov.
In the recent history of human civilization, there are examples of the significant impact of eruptions on the lives of peoples across the planet. For example, in 1815, the Tambora volcano exploded, devastating vast areas in Indonesia. The event had dire consequences: climate change across the planet, resulting in famine, epidemics and unrest. Thus, in the first year after the eruption, there was snow in Canada and northern Europe in the summer. They say that the bicycle owes its appearance to Tambora - most of the horses became extinct, and people became concerned alternative ways movement. Another disaster occurred in 1600, when the Huaynaputina volcano exploded in South America. In Russia, due to air pollution caused by this eruption, crop failure and severe famine occurred in 1601-1603, which ultimately led to the Time of Troubles. Today, Huaynaputina's location makes little difference in the peaceful, hilly landscape of southern Peru.
Now Gorely is a shield volcano of basalt type. It is quite active, eruptions of moderate intensity occur approximately once every 20-40 years. The last one was in 1980, so we can expect the next one in the near future. In the crater of the mountain there is a large fumarole - a hole several meters in size, from which gases come out under extreme pressure. According to scientists, their mass is approximately 11 thousand tons per day (mostly they consist of water (93.5%), but they also contain CO2 and other substances). Such a “factory” has a disproportionately greater effect on the ecosystem than any man-made object created by man.
As a result preliminary analysis seismograms recorded at Gorely, more than 200 earthquakes were identified in just a few days. Scientists used this information to build a seismic model of the subsurface beneath the volcano. However, they had problems specifying the initial model, which they could not immediately overcome. The solution was found by chance.
“In our calculations there is an important determining parameter that must be set in advance, manually - the ratio of the velocities of longitudinal and transverse waves. Typically for volcanoes its value is in the range of 1.7-1.85, but in the case of Gorelye, numbers in this range did not lead to a stable result. Once, by mistake, instead of 1.75, I used the absolutely absurd, as it seemed to me then, value of 1.5 - and suddenly everything fell into place. Subsequent testing showed that it was the most suitable for this case. During a literature review, we found that such anomalously low Vp/Vs values are a fairly clear indicator of the presence of gases in porous rock. This effect, for example, is actively used in oil exploration to separate gas and oil fields,” says Ivan Kulakov.
Thus, Siberian scientists found that the Gorely volcanic structure is a huge steam boiler, saturated with gas under pressure, which cannot escape, since the entire space of the mountain is covered with a thick cover of igneous rocks - basalt flows. Luckily, there's a " safety valve" - that same hole in the crater, only a few meters in size, through which the volcano “releases steam.” If, as a result of some process, this hole becomes clogged with something, an explosion of enormous destructive force can occur.
By the way, the famous Mutnovskaya geothermal power plant is located on the periphery of this steam boiler. Gas here comes to the surface through specially drilled wells, enters turbines under high pressure and is converted into electricity.
Last year, Novosibirsk scientists began researching the Klyuchevskaya group of volcanoes located in Kamchatka. Its uniqueness lies in the fact that it is relatively small area with a size of only about 80 km, volcanoes with fundamentally various compositions and eruption regimes, some of which are record holders in certain categories. Here is the highest fire-breathing mountain in Eurasia - Klyuchevskaya Sopka. In 1956, Bezymyanny Volcano experienced one of the most powerful explosions of the 20th century. The 1976 Tolbachik eruption was one of the most productive in the world in terms of the volume of basaltic lava erupted. “It should also be noted that the volcanoes of this group tend to change their composition quite quickly - within decades. All this indicates a very complex feeding system under the Klyuchevskaya group, which determines the enormous interest of the world scientific community in studying the deep structure beneath it using geophysical methods,” says Ivan Yuryevich.
The scientists decided to start the study from the Tolbachik volcano, where a major eruption occurred a year before the expedition. From November 2012 to August 2013, lava flowed abundantly from the volcano, forming rivers of fire 20-30 kilometers long, covering vast areas. Such massive outpourings should lead to deformations in the earth's crust, which, it is assumed, can be recorded by seismographs. Last summer, Novosibirsk scientists installed 20 seismic stations on Tolbachik (in addition to 10 belonging to the local geophysical service). The work also included geological research and sampling for petrological analyzes carried out by Academician N.L. Dobretsov.
This expedition is a kind of rehearsal for a large-scale study that is planned to be carried out in the coming year. “In 2015, an unprecedented experiment with the sonorous name KISS (Klyuchevskoy Investigation - Seismic Structure of Extraordinary Volcanic System) should take place. It will be carried out by an international team, which, in addition to Novosibirsk residents, will include German and French scientists, as well as specialists from the Kamchatka branch of the Geophysical Service of the Russian Academy of Sciences and the Institute of Volcanology and Seismology of the Far Eastern Branch of the Russian Academy of Sciences. About 80 stations will be located throughout the Klyuchevskaya group (60 of them will be brought from Germany). If they work for one year, this will provide unique data that will allow us to obtain fundamentally new knowledge about the deep feeding mechanisms of volcanoes. “The Klyuchevskaya group is a unique geological object, and you can be sure that the results obtained as part of the planned expedition will attract the attention of the entire world scientific community,” says Ivan Kulakov.
Sources
VKpress (vkpress.ru), 01/20/2015
Scientific Russia (scientificrussia.ru), 01/20/2015
Is humanity ready for catastrophic volcanic eruptions?
At the beginning of January 2019, the Kamchatka volcano Shiveluch, which “awakened” last year, became active. The volcano continues to periodically “shoot out” emissions of ash and gas - experts warn about the danger of its emissions for air travel, at times raising the aviation color code to a dangerous “red”.
Scientists from the Institute of Petroleum Geology and Geophysics SB RAS are exploring the most dangerous volcanoes of Kamchatka
Employees of the Institute of Oil and Gas Geology and Geophysics named after. A.A. Trofimuk SB RAS keeps active volcanoes of Kamchatka under control. Their eruptions can pose a danger to the Pacific air routes and Petropavlovsk-Kamchatsky.
A delegation of the German Academic Exchange Service (DAAD) visited INGG SB RAS
Institute of Oil and Gas Geology and Geophysics named after. A.A. Trofimuk SB RAS was visited by the head of the Moscow branch of DAAD Dr. Andreas Höschen and the head of the DAAD Information Center at NSTU Anna Hess. The guests got acquainted with the work of the Institute and assessed the prospects for the development of international relations.
The Iceland plume is to blame for the melting of the Greenland ice sheet
Scientists have found an explanation for the melting of the Greenland ice shell. Geophysicists have linked the anomalous melting of ice under the central part of the island to the influence of Icelandic hot spot. The research results were published in the prestigious journal Nature Geoscience.
Municipal budgetary educational institution
Lyceum No. 4
Why do volcanoes erupt?
Krivosheev Timur Vladimirovich
3rd grade student
Supervisor:
Krivosheeva Natalya Evgenievna
teacher primary classes
Dankov
2015
Table of contents
1.Introduction………………………………………………………………………………….……...2
Goals and objectives of the research work…………………………………….…2
2. Main part.
2.1 Questioning classmates………………….….….. 3
2.2 Experience No. 1. Movement of magma from the bowels of the earth……………………………5
2.3. Experience No. 2.How does a volcano erupt?…………………..…6
2.4 Experience No. 3.Properties of volcanic stones ………...7
2.5 Consequences of volcanic eruptions…………………….8
3. Conclusions………………………………………………………………………………….…...… 8
4. Conclusion………………………………………………………………………………...8
5. Bibliography……………….…………………………...........9
The year before last, I heard on the news about a volcanic eruption in Russia. The Klyuchevskaya Sopka volcano began to erupt in Kamchatka. I was interested in how and why this volcano woke up. These questions helped me decide on the topic of my research work. I decided to find out why volcanoes erupt.
The purpose of the work is summarize and classify information about volcanoes.Find out the reasons why volcanoes erupt.
Tasks:
Find out what a volcano is?
Study the structure of a volcano.
Find out what kinds of volcanoes there are?
Conduct an experiment and find out how and why a volcano erupts.
Find out what consequences volcanic eruptions have.
Create a working model of a volcano at home.
Learn experimentally about the properties of stones of volcanic origin.
Research methods:
Conversations with adults.
Questioning classmates.
Study and analysis various sources information.
Conducting experiments.
Observations.
Hypothesis:
volcanoes erupt because there is a lot of liquid magma under the earth's crust, and therefore it comes out.
Questioning classmates
I began my search for reasons explaining why volcanoes erupt by conducting a survey among my classmates.
To the question “Why do volcanoes erupt?” The guys gave the most votes to the answer “from an earthquake.” They also believe that the sun and geographic location have a special influence on volcanic eruptions.
What is a volcano
From the Internet I learned that the word “Vulcan” comes from the name of the island of Vulcano off the coast of Italy, where, according to legend, one of the forges of the ancient Roman god of fire Vulcan (Hephaestus) was located.
I read in the encyclopedia that a volcano is a geological formation that appears above channels and cracks in the earth's crust, through which lava, volcanic gases and stones erupt onto the earth's surface.
Types of volcanoes:
Active - These are volcanoes that erupt regularly.
Extinct - These are volcanoes whose activity has ceased and they no longer erupt.
Asleep - these are volcanoes that were considered extinct, but suddenly began to act.
A volcano consists of: MAGMA OR LAVA - molten rocks saturated with gases. VENT - a channel through which magma rises to the crater. Crater - a bowl-shaped depression at the top of a volcano.
To find out where magma comes from, I first studied the structure of our planet. I learned that the Earth resembles an egg: on top there is a thin hard shell - the earth's crust, underneath there is a viscous layer of hot mantle, and in the center there is a solid core.
Inside the Earth, due to temperature differences, there is a constant movement of the mantle. Pieces of the earth's crust (tectonic plates) also move along with it.When plates collide, one plate goes down and begins to melt - turns into magma. Magma rises to the surface and accumulates in magma chambers.
Experience No. 1. Movement of magma from the depths of the earth
I decided to experimentally see what happens to magma during a collision tectonic plates. To do this, I conducted my first experiment, “Movement of magma from the bowels of the Earth.” To do this, I immersed solid chocolate bars, which replaced tectonic plates, in “magma” yoghurt. Using sticks, I began to move my “tectonic plates.” The “plates” began to collide with each other, some plates went under others, and at this point the “magma” was pushed to the surface of the “plates”.
Conclusion:
The experience helped to understand how, under the influence of the movement of tectonic plates, magma moves to the surface of the earth.
Magma rises to the surface and accumulates in magma chambers. There it is under pressure, just like carbonated drinks in a closed bottle.
The gases that make up the magma tend to go out and lift the magma along the crater of the volcano. These gases are flammable, so they ignite and explode in the crater of a volcano. Gases, ash, hot rocks and magma burst out through the crater of the volcano.
Experience No. 2. How does a volcano erupt?
My second experience helped me figure out why magma starts to erupt from a volcano. I made a cone out of paper and gave it the color of a volcano. Place a glass inside the cone. Filled the glass with “lava” - a mixture of baking soda, liquid soap and red paint. Filled a volcano with vinegar and caused an eruption.
Conclusion:
The gas formed when vinegar reacts with soda raises the “lava” upward and an “eruption” occurs.
Experience No. 3. Properties of volcanic stones
For a long time I was passionate about collecting the collection of stones “Minerals. Treasures of the Earth." From it I learned that stones of volcanic origin were formed as a result of volcanic eruptions and the cooling of volcanic magma. They are characterized by durability, high density and good hardness. But there is one stone that is formed when magma releases a lot of gases, it foams and cools. This is pumice.
This stone has porous structure. The pores are filled with air. Therefore, pumice does not sink. I decided to test this experimentally. I took stones of volcanic origin from the collection: granite, obsidian, gneiss, galena, basalt, andesite and pumice. Immersed them in water. All the stones sank, but the pumice remained on the surface of the water.
Conclusion:
Pumice is a rock of volcanic origin that does not sink in water.
Consequences of volcanic eruptions
Volcanic eruptions have a strong negative influence, bring colossal destruction and death.
But these fire-breathing mountains also give man hot water, energy, various rocks, metals and even gems. Volcanic ash increases soil fertility, so volcanoes bring not only destruction, but also benefit.
Conclusions
1. While working on this project, I plunged into the world of fascinating experiences, became acquainted with the structure of a volcano and the process of its eruption, and learned that volcanoes bring not only harm, but also benefit.
2. My hypothesis that a volcanic eruption occurs because there is too much magma was partially confirmed. As a result of my research and experiments, I concluded that a volcanic eruption occurs because magma is lifted to the surface of the Earth by the gases contained in it.
Conclusion
I found the answer to my question "Why do volcanoes erupt". I would like morestudy the giant volcanoes in more detail and find out whether it is possible to predict and eliminate the consequences of the eruptions of these giants.
I also want to present my work to my classmates and hope to get them interested in my research.
http://www.stranamam.ru/post/5375998/ 2. “Volcanoes” Aprodov V.A.3. “Volcanoes” by Christina Godin, Children's Encyclopedia Machaon
4. Encyclopedia. “Minerals. Treasures of the earth."
5. Great Russian Encyclopedia / Ch. ed. Yu. S. Osipov. - M.: Scientific. publishing house "BRE", 2004.
Nikolai Shapiro, Doctor of Geological and Mineralogical Sciences, leading researcher at the Institute of Physics of the Earth (Paris) and the Institute of Volcanology and Seismology, Far Eastern Branch of the Russian Academy of Sciences, Professor of the Russian Academy of Sciences
Evgeniy Gordeev, Doctor of Physical and Mathematical Sciences, Director of the Institute of Volcanology and Seismology, Far Eastern Branch of the Russian Academy of Sciences, Academician of the Russian Academy of Sciences
Danila Chebrov, Candidate of Physical and Mathematical Sciences, Director of the Kamchatka Branch of the Unified Geophysical Service of the Russian Academy of Sciences
"Kommersant Science" No. 5, July 2017
Unique observations of deep low-frequency earthquakes obtained by Russian scientists in Kamchatka allow us to trace magmatic processes in the lower layers of the earth's crust. Computer processing of seismic records that preceded the major eruption of the Tolbachik volcano will clarify the patterns of volcanic activity and will make it possible to more reliably predict eruptions.
Main practical purpose volcanology - development of methods for monitoring volcanic activity in order to timely and reliably predict eruptions. There are more than 1,500 volcanoes on Earth that have erupted at least once over the past 10 thousand years, of which about 600 have erupted in historical era. Each year there are between 50 and 70 eruptions.
Most of the active volcanoes are located in the so-called subduction zones of the Pacific Ring of Fire, where oceanic lithosphere subsides into the mantle. At depths between 100 and 200 km, the interaction of the sinking ocean lithosphere and the mantle produces magmatic melts, which then rise to the Earth's surface and lead to volcanism.
Slow and fast volcanic processes
The main force driving magma to the surface is the difference in density between the relatively “cold” and heavy rocks of the mantle and crust and the heated, fluid-containing and relatively light magmatic melts. Moreover, along most of the path to the surface, magmatic melts do not rise directly, but seep through the porous medium. Therefore, the speed of their rise depends on the porous properties of the mantle and crust and on the viscosity of the magma itself. The chemical composition and physical properties (density, viscosity) of magmatic melts as they rise can change significantly due to interaction with surrounding rocks and due to changing pressure and temperature. The density and porosity of surrounding rocks also change with depth.
Most of the active volcanoes are located in the so-called subduction zones of the Pacific Ring of Fire, where oceanic lithosphere subsides into the mantle
As a result, the process of magma rising to the surface is heterogeneous. Overall this is happening very slowly. Individual volcanic systems can develop over thousands or even millions of years. During this time, magma gradually accumulates in intermediate chambers, the closest of which are located at a depth of several kilometers. But this process is very nonlinear, and certain stages of it can occur very quickly, leading to sharp local accelerations of magma movement and sharp pressure surges. Such accelerations can be caused by sudden changes physical and chemical properties(phase transitions), which, among other things, often lead to the release of a gas fraction in the magma. The activation of such processes can begin from several days to several years before the eruption.
Methods for studying volcanoes
The main difficulty in studying volcanoes is that the geological processes leading to eruptions occur at great depths. Scientists obtain a significant amount of information about the origin and history of volcanoes using geological methods - through the study of igneous volcanic rocks, as well as extinct volcanic systems, the deep parts of which come to the surface after the weathering of the rock.
But when studying the current state of volcanoes and identifying the preparation of eruptions, geophysical observations become the main source of information about deep processes. The leading geophysical method is seismological monitoring. Its main idea is that many deep processes occurring in volcanic systems can generate seismic waves. To observe them, seismographs are installed near volcanoes - instruments that record vibrations of the Earth's surface.
Volcanic earthquakes
Seismic manifestations of deep volcanic activity, or so-called volcanic earthquakes, are numerous and varied. Among them, two main types can be distinguished.
The first type is called volcano-tectonic earthquakes because their properties and origin are similar to ordinary tectonic earthquakes. The activation of volcanoes is primarily associated with an increase in pressure in magma chambers and the acceleration of the rise of magma to the surface. These processes increase mechanical stress in the earth's crust under volcanoes, with the subsequent activation of numerous microfaults, which generate volcano-tectonic earthquakes.
The second type of volcanic earthquakes is generated directly in magma supply channels. With the accelerated movement of magma or volcanic gases through these channels, sharp pressure surges often occur, accompanied by seismic waves. The main characteristic of such sources is that they emit waves at relatively low frequencies - in the range from 1 to 5 hertz. Typical wave frequencies characteristic of volcano-tectonic earthquakes are 10 hertz or more.
The overwhelming majority of volcanic earthquakes are very weak and are not felt on the surface. But they are well recorded by sensitive seismographs
The overwhelming majority of volcanic earthquakes are very weak and are not felt on the surface. But they are well recorded by sensitive seismographs. The appearance of recorded volcanic earthquakes and a progressive increase in their number is the most reliable sign of the activation of volcanic systems. Counting recorded earthquakes is the simplest method of seismic monitoring of volcanoes. And if observation systems of many instruments are placed on volcanoes, volcanologists have the opportunity to determine the location and magnitude (this is an energy characteristic) of volcanic earthquakes, which, in turn, makes it possible to characterize deep-seated volcanic processes in more detail.
In some cases, it is possible to trace the migration of seismic activity from depth to the surface. Such observations are especially valuable when derived from low-frequency earthquakes, as they relate to the propagation of magma in feeder conduits beneath volcanoes. And this movement of magma plays a decisive role in the preparation of an eruption. Using detailed observations of low-frequency earthquakes, it is possible to better understand the processes that control the feeding of volcanoes with magma from depth.
Volcano laboratories
But high-quality observations of the processes described are rarely obtained. Most active volcanoes do not have modern geophysical observation systems, and conversely, many of the well-observed volcanoes are dormant most of the time. Therefore, for the development of geophysical research and monitoring methods, a few volcanoes are very important - natural laboratories that erupt frequently and are studied in detail. Fine famous examples Such volcanoes are Kilauea on the Hawaiian Islands, Piton de la Fournaise on the French island of Reunion, Etna and Stromboli in Italy. These volcanoes erupt almost constantly (Kīlauea) or very frequently, and their eruptions are observed in detail by volcanological observatories that maintain modern systems geophysical observations.
Most scientific works aimed at understanding volcanic earthquakes and related deep processes, is based on observations obtained precisely in such laboratory volcanoes.
Unique data from Russian volcanoes
Russia is a country with a large number of active volcanoes. Almost all of them are on Far East in the Kuril-Kamchatka subduction zone. A special place among Russian and world volcanic systems is occupied by the Klyuchevskaya northern group, where four very active volcanoes are located not far from each other: Klyuchevskaya has been active for several thousand years; Shiveluch - since August 1980 (since the start of the growth of the lava dome in the crater formed during the catastrophic eruption on November 12, 1964); Nameless - from October 22, 1955 (from the moment of awakening after a thousand years of silence); On Tolbachik volcano, large fissure eruptions occurred in 1975–1976 and in 2012–2013. The area also contains 12 weakly active or extinct volcanoes and about 400 smaller volcanic formations.
Systematic observations in this area began with the creation of the Kamchatka volcanological station in the village of Klyuchi in 1935. The first permanently operating seismograph at this station was installed in 1946. Currently, scientific units of the Institute of Volcanology and Seismology (IViS) of the Far Eastern Branch of the Russian Academy of Sciences and the Kamchatka branch of the Federal Research Center “Unified Geophysical Service of the Russian Academy of Sciences” (KF FRC EGS RAS) are conducting observations on the Klyuchevskaya group of volcanoes. They support a network of 18 permanent seismographs.
Since the mid-1990s, seismic information has been converted into digital format and, on this basis, an archive of continuous seismic records has been created for more than 20 years, during which many dozens of eruptions occurred. This set of observations about the seismic activity of volcanoes has no analogues in the world. One of its unique characteristics is the simultaneous observation of very different volcanoes, which makes it possible to establish the relationship between their activities. Other distinctive feature - large number low-frequency volcanic earthquakes at great depths corresponding to the crust-mantle boundary.
Recently, our joint scientific group of IViS and KF FRC EGS RAS, created with the support of the Russian Science Foundation, carried out a detailed analysis of the data obtained. To do this, we carried out intensive computer processing of seismic records for two years preceding the last major eruption of the Tolbachik volcano.
The results found that the activity of deep low-frequency events increased in the two years before the eruption. This corresponded to a gradual activation and increase in pressure in a deep magma chamber, which is located at a depth of approximately 30 km, that is, at the boundary of the earth’s crust and mantle. Maximum seismic activity at depth was reached five months before the eruption. Maximum quantity low-frequency earthquakes in near-surface magma chambers were recorded several months later. We interpreted this delay as the time required for magmatic pressure to propagate from a depth of 30 km to the surface. The rather slow spread of pressure can be explained by the fact that in the lower part of the feeding system, magma does not migrate through an open channel (as is often depicted in textbooks and encyclopedias), but seeps through a porous medium.
Seismic observations obtained at the Klyuchevskaya group of volcanoes contain a huge amount of information that has yet to be analyzed and comprehended. For its full use, it is necessary to develop fundamentally new methods for analyzing geophysical data using modern computer technologies, including machine learning. The implementation of such automated methods is becoming increasingly urgent for processing large data streams in geophysical monitoring of volcanoes and earthquakes. The progress of modern methods will make it possible to prevent the intensification of volcanic activity. And preventing eruptions is one of the most important tasks modern volcanology.
Introduction
I would like to present to your attention a work on the topic “Volcanoes”. I chose this topic because I once read Jules Verne's book Journey to the Center of the Earth. I realized that this is a very interesting and unusual natural phenomenon. And I wanted to learn as much as possible about volcanoes.
Relevance of the study determined by the need to forecast and assess the danger of volcanic eruptions.
Object of study: volcanoes
Item: volcano model
Purpose of the study: simulate a working volcano model at home
Tasks:
- study additional literature and select interesting information, about what it is - a volcano;
- find out how a volcano works;
- find out what volcanoes are;
- create a working model of a volcano at home;
- conduct an experiment
Hypothesis: Is it possible to create a working model of a volcano at home?
Research methods: study and analysis of popular science literature
Volcanoes
The word "volcano" comes from the name of the ancient Roman god of fire, Vulcan. The science that studies volcanoes is volcanology.
Volcanoes are geological formations on the surface of the Earth's crust or the crust of another planet, where magma (a mass of molten rock located underground at very great depths) comes to the surface, forming lava, volcanic gases, rocks (volcanic bombs) and pyroclastic flow (a mixture of high-temperature volcanic gases, ash and rocks). The flow speed sometimes reaches 700 km/h, and the gas temperature is 100 - 800 o C.
Volcanoes can be active or dormant. An active volcano often erupts lava, ash and dust. When a volcano does not erupt for many years, it is called dormant. However, dormant volcanoes can begin to erupt even after a long period of inactivity. When eruptions finally stop, such a volcano is called extinct. Some volcanoes are distinguished by violent and colorful eruptions: fiery lava and hot clouds of gases are thrown high into the air. From other volcanoes, lava flows slowly and slowly, like boiling syrup and hot tar.
The structure of the volcano.
A crater is a depression in the form of a bowl or funnel formed on the top or slope of a volcano as a result of its active activity. The diameter of the crater can be from tens of meters to several kilometers, the depth - from tens to several hundred meters.
A vent is a channel through which lava moves.
Magma is a viscous liquid consisting of a mixture of various molten minerals and some mineral crystals that forms in the depths of the Earth. It resembles melting snow or frozen slush with ice crystals. Magma also contains water and dissolved gases.
Lava is magma poured onto the surface. Temperature 750 - 1250 oC.
Current speed is 300-500 meters per hour.
Depending on your chemical composition lava can be liquid or thick and viscous. When magma rises through the earth's crust and comes to the surface, it is called an -Eruption.
Classification of volcanoes by shape
There are different forms of volcanoes, some of them are much more dangerous than others
Shield volcanoes (Fig. 1) are formed as a result of repeated emissions of liquid lava. This shape is characteristic of volcanoes that erupt low-viscosity basaltic lava: it flows from both the central crater and the slopes of the volcano. Lava spreads evenly over many kilometers. Like, for example, on the Mauna Loa volcano in the Hawaiian Islands, where it flows directly into the ocean.
Cinder cones (Fig. 2) eject from their vents only such loose substances as stones and ash: the largest fragments accumulate in layers around the crater. Because of this, the volcano becomes higher with each eruption. Light particles fly away over a longer distance, which makes the slopes gentle.
Stratovolcanoes, (Fig. 3) or “layered volcanoes,” periodically erupt lava and pyroclastic matter - a mixture of hot gas, ash and hot stones. Therefore, deposits on their cone alternate. On the slopes of stratovolcanoes, ribbed corridors of solidified lava are formed, which serve as support for the volcano.
Dome (Fig. 4) volcanoes form when granitic, viscous magma rises above the rim of the volcano's crater and only a small amount seeps out, flowing down the slopes. Magma clogs the volcano's crater, like a cork, which the gases accumulated under the dome literally knock out of the crater. Volcanoes-calderas. (Fig. 5) they explode so violently that they destroy themselves. Their eruptions are accompanied by very strong pyroclastic explosions. These volcanoes killed the largest number of people, and the consequences of their explosions made the surrounding areas deserted.
Eruption process.
Our planet Earth resembles an egg: on top there is a thin hard shell - the earth's crust, underneath there is a viscous layer of hot mantle, and in the center there is a solid core. The earth's crust is called the lithosphere, which is translated from Greek as “stone shell.” The thickness of the lithosphere is on average about 1% of the radius globe. On land it is 70-80 kilometers, but in the depths of the oceans it can be only 20 kilometers. The temperature of the mantle is thousands of degrees. Closer to the core, the temperature of the mantle is higher, closer to the crust - lower. Due to the difference in temperature, the substance of the mantle is mixed: hot masses rise upward, and cold masses descend (just like boiling water in a pan or kettle, but this only happens thousands of times slower). The mantle, although heated to enormous temperatures, is due to the colossal pressure in the center of the Earth not liquid, but viscous, like very thick tar. The lithosphere seems to float in a viscous mantle, submerging slightly into it under the weight of its weight.
Reaching the base of the lithosphere, the cooling mass of the mantle moves horizontally for some time along the solid rock “shell”, but then, having cooled, it descends again towards the center of the Earth. While the mantle moves along the lithosphere, pieces of the earth's crust (lithospheric plates) inevitably move along with it, while individual parts of the stone mosaic collide and creep onto each other.
The part of the plate that was below (on which another plate crawled) gradually sinks into the mantle and begins to melt. This is how magma is formed - a thick mass of molten rocks with gases and water vapor. Magma is lighter than the surrounding rocks, so it slowly rises to the surface and accumulates in so-called magma chambers. They are most often located along the plate collision line.
The behavior of hot magma in a magma chamber really resembles yeast dough: magma increases in volume, occupies all available space and rises from the depths of the Earth along cracks, trying to break free. Just as dough lifts the lid of a pan and flows over the edge, so magma breaks through the earth's crust in the deepest weak points and bursts to the surface. This is a volcanic eruption.
A volcanic eruption occurs due to degassing of magma, that is, the release of gases from it. Everyone knows the process of degassing: if you carefully open a bottle of a carbonated drink (lemonade, Coca-Cola, kvass or champagne), a pop is heard, and smoke appears from the bottle, and sometimes foam - this is gas coming out of the drink (that is, it is degassing) .
Products of volcanic eruptions. An eruption is caused by magma breaking through the earth's crust. Most eruptions occur when a volcanic conduit or volcanic crater is blocked. Due to the magma coming from below, the pressure increases. When the plug blocking the channel breaks and the pressure is released, the gas in the magma bubbles boils, like a fizzy drink.
This is what causes a volcano to explode. When a volcano erupts, it sends out not only liquid lava, but also large chunks of solidified lava - called bombs - that crash to the ground up to two miles from the crater. Ash and volcanic gases form columnar volcanic clouds, sometimes rising to great heights.
The main products of an eruption are lava, ash, and other substances that come to the surface of the earth after the activity of the volcano. Volcanoes can emit significant amounts of toxic gases. Volcanic gases released by volcanoes rise into the atmosphere, but some of them can return to the surface of the earth in the form of acid rain. Quite serious consequences of acid rain for the body and health can be observed with manganese poisoning, which can also be found in rainwater in huge quantities.
Where are volcanoes common?
The Pacific coast of Central America is one of the most active areas of volcanic activity in the world. And in fact, more than two-thirds of the active volcanoes are located in this place, as well as many that ceased their activity relatively recently.
The reason is this: in these places the earth's crust is very weak compared to other areas of the globe. Where there is a weak section of the earth's crust, a volcano appears.
Main areas of volcanic activity (Fig. 5.)
Modeling current model volcano at home
DIY volcano model
But I can’t wait to touch everything with my own hands and see everything in reality - these splashes of fire, sparkling creeping lava, escaping clouds of smoke and splashes of a fountain of stones. This fiery spectacle will help us make a DIY Vulcan kit. Following strictly according to the instructions, using scissors, newsprint, adhesive paste, armed with the basics of geometry, we painstakingly make a model of our volcano step by step. The model is done, all that remains is to simulate a volcanic eruption
Conducting an experiment. Volcanic eruption.
After reading one of the articles on the Internet, I learned that you can simulate a volcanic eruption at home.
I needed the following materials for the experiment:
- baking soda (2 tablespoons)
- citric acid (70 m.l.)
- glass or iron jar (150 ml.)
- plasticine of different colors
- dishwashing detergent
Progress of the experiment:
1) Take the made model of the volcano
2) Pour 2 tbsp into the “crater”. soda
3) Pour 2 tbsp. dishwashing liquid
4) Pour in 50-70 ml citric acid
5) Watching a “volcanic eruption”
Experiment:
-add more dishwashing liquid;
-add more vinegar;
-add small pieces of foam.
From the experiment we can draw the following conclusion. When baking soda and citric acid are combined, a chemical reaction occurs, releasing carbon dioxide, which bubbles, causing the mass to overflow over the edges of the “crater,” and the dishwashing detergent causes the “lava” to bubble more strongly. This chemical reaction has not only an external effect, but also a practical one: it is very popular in cooking. Housewives “quench” soda with vinegar and add it to the dough; the released carbon dioxide makes the dough fluffy, forming bubbles and air tracks in it.
This is how, in a playful way, I showed and explained the nature of the occurrence of volcanoes on Earth.
Conclusion
Having studied and analyzed popular scientific literature in detail, I learned a lot of new and interesting things about volcanoes. In fact, the volcano erupts because magma has accumulated in the volcanic chamber and, under the influence of the gas included in its composition, it rises to the top. In the crater of a volcano, the amount of gas becomes greater. The magma turns to lava, reaches the crater and erupts. Also that volcanoes have great value in nature. They carry with them both destructive and creative power. We can only observe and explain what is happening. Man cannot stop, change, or even prevent these formidable natural phenomena.
With the help chemical reaction I showed and explained the nature of the occurrence of volcanoes on Earth. Thus, he satisfied his cognitive interest, and also interested his classmates in this experiment.
02:26 — REGNUM Long-period volcanic earthquakes, or more precisely, an increase in their activity, directly foreshadow volcanic eruptions. This is stated in a study by scientists published in the journal Nature GeoScience after large-scale observations of the Klyuchevskaya group of volcanoes in Kamchatka, the correspondent reports. IA REGNUM.
According to volcanologists, the mechanism of earthquakes that occur under volcanoes is not similar to “ordinary” tremors that are caused by the movement of tectonic plates.
“Earthquakes that occur under giants are caused by the movement of magma and changes in pressure in the magma chamber. Long-period volcanic earthquakes are observed all over the world, but most often they are localized very close to the surface, that is, at a depth of the first hundreds of meters - kilometers. But deep earthquakes are especially interesting: they correspond to the activation of the deepest part of the magmatic system and are one of the very first harbingers of an upcoming eruption,” - explained a leading researcher at the Institute of Volcanology and Seismology of the Far Eastern Branch of the Russian Academy of Sciences and the Seismology Laboratory of the Institute of Earth Physics in Paris Nikolai Shapiro, the words of which are quoted by the website of the Russian Science Foundation.
In Kamchatka, scientists studied the Klyuchevskaya group of volcanoes, which has a deep source located at a depth of about 30 km. From it, magma rises through a complex system of channels into smaller chambers located under each volcano.
For two years, geophysicists conducted observations before the large eruption of the Plosky Tolbachik volcano, which began on November 27, 2012. As a result, the scientists found that the activity of deep long-period events increased in the two years before the Plosky Tolbachik eruption, which corresponds to a gradual activation and increase in pressure in the deep magma chamber. The maximum seismic activity at depth was reached several months before the eruption of Plosky Tolbachik.
“We were able to establish a connection between long-period earthquakes at depth and in a shallow near-surface source and, thus, determine how long it took for activity to move from depth to the surface. We measured that the time between peaks of activity is about 2−3 months. Most likely, it was precisely this time interval that was needed for the pressure in the magmatic system to spread from depth to the surface,” - Nikolai Shapiro comments.
As reported IA REGNUM, the ashfall zone around the Kambalny volcano in Kamchatka left all animals - foxes, wolverines, ducks and even crows. As experts from the Kronotsky Nature Reserve suggest, this is due to the fact that in the reservoirs closest to the volcano, the water is poisoned by volcanic ash.
Kambalny is the southernmost volcano of Kamchatka. It began to erupt on March 25, 2017. Before this, nothing was known about its activity - for many centuries there is not a single evidence of its eruption. Volcanologists installed a video camera to record the activity of the volcano.