A report about volcanoes, geological formations on the surface of the crust in which magma comes to the surface and forms volcanic gases, lava, and stones.
Message about volcanoes
What is a volcano?
From Latin the word “volcano” means fire, flame. In the depths of the Earth under the influence high temperatures melting of rocks with magmatic formation occurs. During this process, large amounts of gaseous substances are released. The volume of melt and the pressure on solid rocks increases significantly. Magma begins to move towards areas of lower pressure up to the surface. Cracks in the earth's crust begin to fill with liquid rocks, and when they burst, they raise entire layers of the crust.
Magma may partially overtake, forming laccoliths and magma veins. During volcanic eruptions, the other part comes to the surface in the form of volcanic ash, lava, gases, rock fragments and lava ingots.
Types of volcanoes
These geological formations are of 2 types:
- Cracked
They do not rise high enough above the Earth's surface. Fissure volcanoes are cracks from which magma flows to the surface. But there are very few of them on the planet.
- Central
They are a cone of great height, from which magma and lava come out during eruptions. Such a volcano has a vent (magma flows through it) and craters (an opening from which magma comes to the surface).
Volcanoes are also divided into extinct, active and dormant. Dormant volcanoes on this moment do not erupt, although local earthquakes constantly occur beneath them. And extinct means that there is no volcanic activity.
How many volcanoes are there on Earth?
There are 1,500 volcanoes on the planet, both active and extinct. The most famous of them are Klyuchevskaya Sopka (Kamchatka), Elbrus (Caucasus), Kilimanjaro (Africa), Fuji (Japan).
Most of them are located along the perimeter Pacific Ocean. They form the so-called “ring of fire”. The most active volcanic zone is the Mediterranean-Indonesian belt. Volcanic eruptions occur according to a certain pattern - their location in seismic areas, moving areas.
- The largest volcano on the planet is Mauna Loa. It occupies almost the entire part of the Hawaiian island and is the most active.
Famous volcanic eruptions in history: interesting facts
- (Italy). The eruption occurred on August 24, 79. It destroyed the city of Pompeii, covering it with a layer of dust up to 8 m, as well as Herculaneum and Stabiae. The ashes of Vesuvius flew to Syria and Egypt. Today it is the only active volcano in Europe. In total, more than 80 eruptions were recorded. The last of them was in 1944.
- Tambora (Sumbawa Island). The eruption occurred on April 5, 1815. IN modern history This is the largest eruption in terms of volume of material ejected and death toll. He completely destroyed the Tambora culture, which Europeans had discovered shortly before. The volcano erupted for 10 days and decreased in height by 1400 m. It covered an area of 500 km with ash, and the sun did not shine through it for 3 days.
- Volcano Taupo (New Zealand). The eruption occurred 27 thousand years ago, and scientists consider it the most powerful in the entire history of the planet. As a result of his active work, Lake Taupo was formed. The last time the volcano erupted was in 180 AD. e. Its blast wave and ash destroyed half of the North Island. 100 km 3 of tectonic matter was released into the atmosphere.
- Volcano Krakatoa (Indonesia). The eruption occurred on August 27, 1883. It caused a 30-meter tsunami that washed away 295 towns and villages. Pieces of lava flew to a height of 55 km. The ash covered an area of 5330 km. The blast wave circled the planet up to 11 times. The Krakatoa explosion was 200,000 times more powerful than the Hiroshima explosion. Scientists suggest that he previously woke up in 535 and the islands of Sumatra and Java may have been formed from his activities. After the 1883 eruption, the Krakatoa volcano collapsed. And in its place in 1927 a new active volcano appeared - Anak Krakatoa.
- Volcano Santorini (Greece). The eruption occurred 1.5 thousand years BC. And it destroyed the Cretan civilization, and also contributed to the sinking of the island of Thera. This is not his only eruption. In 1886 he whole year spewed pieces of lava directly from the sea to a height of 500 meters.
- Volcano Montagne-Pelée (Martinique). The eruption began in April 1902. Already on May 8, it covered the city located in an 8-kilometer zone from it with dust. Near Martinique, the seabed dropped a couple of hundred meters.
- Volcano Nevado del Ruiz (Colombia). The eruption began on November 13, 1985, and within just 10 minutes, the city of Armero with a population of 29,000 people was destroyed.
- Volcano Pinatubo (Philippines). For 622 long years it was considered extinct. But on June 12, 1991, it destroyed 18 km of territory along itself. The consequence of such a disaster is a decrease in temperature and a decrease in the ozone layer, which contributed to the formation of a large ozone hole.
- Katmai Volcano (Alaska). Its eruption on June 6, 1912 was the largest in the history of the 20th century.
We hope that the report on volcanoes for children helped you prepare for the lesson. You can leave your message about volcanoes using the comment form below.
The ancient Romans, watching black smoke and fire bursting into the sky from the top of the mountain, believed that before them was the entrance to hell or to the domain of Vulcan, the god of blacksmithing and fire. In honor of him, fire-breathing mountains are still called volcanoes.
In this article we will figure out what the structure of the volcano is and look into its crater.
Active and extinct volcanoes
There are many volcanoes on Earth, both dormant and active. The eruption of each of them can last days, months, or even years (for example, the Kilauea volcano, located in the Hawaiian archipelago, awoke back in 1983 and its activity still does not stop). After which the craters of volcanoes are able to freeze for several decades, only to then remind of themselves again with a new eruption.
Although, of course, there are also geological formations whose work was completed in the distant past. Many of them still retain the shape of a cone, but there is no information about exactly how their eruption occurred. Such volcanoes are considered extinct. As an example, Kazbek can be cited, since ancient times covered with shining glaciers. And in Crimea and Transbaikalia there are heavily eroded and destroyed volcanoes that have completely lost their original shape.
What types of volcanoes are there?
Depending on the structure, activity and location, in geomorphology (the so-called science that studies the described geological formations) separate types of volcanoes are distinguished.
IN general view they are divided into two main groups: linear and central. Although, of course, this division is very approximate, since most of them are classified as linear tectonic faults in the earth’s crust.
In addition, there are also shield-shaped and dome structures of volcanoes, as well as so-called cinder cones and stratovolcanoes. By activity they are defined as active, dormant or extinct, and by location - as terrestrial, underwater and subglacial.
How do linear volcanoes differ from central ones?
Linear (fissure) volcanoes, as a rule, do not rise high above the surface of the earth - they have the appearance of cracks. The structure of volcanoes of this type includes long supply channels associated with deep splits in the earth's crust, from which liquid magma of basaltic composition flows. It spreads in all directions and, when solidified, forms lava covers that erase forests, fill depressions, and destroy rivers and villages.
In addition, during the explosion of a linear volcano, explosive ditches may appear on the earth's surface, extending several tens of kilometers. In addition, the structure of the volcanoes along the fissures is decorated with gentle shafts, lava fields, spatter and flat wide cones, radically changing the landscape. By the way, the main component of Iceland's relief is lava plateaus, which arose in this way.
If the composition of the magma turns out to be more acidic (increased content of silicon dioxide), then extrusive (i.e. squeezed out) shafts with a loose composition grow around the mouth of the volcano.
The structure of central type volcanoes
A central type volcano is a cone-shaped geological formation, which is crowned on top by a crater - a depression shaped like a funnel or bowl. It, by the way, gradually moves upward as the volcanic structure itself grows, and its size can be completely different and measured in both meters and kilometers.
A vent leads deep into the crater, through which magma rises up into the crater. Magma is a molten fiery mass that has a predominantly silicate composition. It is born in the earth's crust, where its hearth is located, and having risen to the top, it pours out onto the surface of the earth in the form of lava.
An eruption is usually accompanied by the release of small sprays of magma, which form ash and gases, which, interestingly, are 98% water. They are joined by various impurities in the form of flakes of volcanic ash and dust.
What determines the shape of volcanoes
The shape of a volcano largely depends on the composition and viscosity of the magma. Easily mobile basaltic magma forms shield (or shield-like) volcanoes. They tend to be flat in shape and have a large circumference. An example of these types of volcanoes is the geological formation located in the Hawaiian Islands and called Mauna Loa.
Cinder cones are the most common type of volcano. They are formed during the eruption of large fragments of porous slag, which, piling up, build a cone around the crater, and their small parts form sloping slopes. Such a volcano grows higher with each eruption. An example is the Plosky Tolbachik volcano that exploded in December 2012 in Kamchatka.
Structural features of dome and stratovolcanoes
And the famous Etna, Fuji and Vesuvius are examples of stratovolcanoes. They are also called layered, since they are formed by periodically erupting lava (viscous and quickly solidifying) and pyroclastic matter, which is a mixture of hot gas, hot stones and ash.
As a result of such emissions, these types of volcanoes have sharp cones with concave slopes, in which these deposits alternate. And lava flows from them not only through the main crater, but also from cracks, solidifying on the slopes and forming ribbed corridors that serve as support for this geological formation.
Dome volcanoes are formed with the help of viscous granite magma, which does not flow down the slopes, but solidifies at the top, forming a dome, which, like a cork, plugs the vent and is expelled by gases accumulated under it over time. An example of such a phenomenon is the dome that forms over Mount St. Helens in the northwestern United States (it formed in 1980).
What is a caldera
Described above central volcanoes They usually have a cone shape. But sometimes, during an eruption, the walls of such a volcanic structure collapse, and calderas are formed - huge depressions that can reach a depth of thousands of meters and a diameter of up to 16 km.
From what was said earlier, you remember that the structure of volcanoes includes a huge vent through which molten magma rises during an eruption. When all the magma is on top, a huge void appears inside the volcano. It is precisely into this that the top and walls of a volcanic mountain can fall, forming on the earth’s surface vast cauldron-shaped depressions with a relatively flat bottom, bordered by the remains of the crash.
The largest caldera today is the Toba caldera, located in (Indonesia) and completely covered with water. The lake formed in this way has very impressive dimensions: 100/30 km and a depth of 500 m.
What are fumaroles?
Volcanic craters, their slopes, foothills, and the crust of cooled lava flows are often covered with cracks or holes from which hot gases dissolved in the magma escape. They are called fumaroles.
As a rule, thick white steam billows over large holes because magma, as already mentioned, contains a lot of water. But besides this, fumaroles also serve as a source of release of carbon dioxide, all kinds of sulfur oxides, hydrogen sulfide, hydrogen halides and other chemical compounds that can be very dangerous for humans.
By the way, volcanologists believe that the fumaroles included in the structure of the volcano make it safer, since gases find a way out and do not accumulate in the depths of the mountain to form a bubble that will eventually push the lava to the surface.
Such a volcano includes the famous one, which is located near Petropavlovsk-Kamchatsky. The smoke billowing above it can be seen tens of kilometers away in clear weather.
Volcanic bombs are also part of the structure of Earth's volcanoes
If a long-dormant volcano explodes, then during the eruption the so-called volcanoes fly out of its crater. They consist of fused rocks or fragments of lava frozen in the air and can weigh several tons. Their shape depends on the composition of the lava.
For example, if lava is liquid and does not have time to cool sufficiently in the air, a volcanic bomb that falls to the ground turns into a cake. And low-viscosity basaltic lavas rotate in the air, thereby taking on a twisted shape or becoming like a spindle or pear. Viscous - andesitic - pieces of lava after falling become like a bread crust (they are round or multifaceted and covered with a network of cracks).
The diameter of a volcanic bomb can reach seven meters, and these formations are found on the slopes of almost all volcanoes.
Types of volcanic eruptions
As N.V. Koronovsky pointed out in the book “Fundamentals of Geology,” which examines the structure of volcanoes and types of eruptions, all types of volcanic structures are formed as a result of various eruptions. Among them, 6 types stand out in particular.
When did the most famous volcanic eruptions occur?
The years of volcanic eruptions can, perhaps, be considered serious milestones in the history of mankind, because at this time the weather changed, a huge number of people died, and even entire civilizations were erased from the Earth (for example, as a result of the eruption of a giant volcano, the Minoan civilization died in 15 or 16 c. BC).
In 79 AD e. Vesuvius erupted near Naples, burying the cities of Pompeii, Herculaneum, Stabia and Oplontium under a seven-meter layer of ash, leading to the death of thousands of inhabitants.
In 1669, several eruptions of Mount Etna, as well as in 1766, of Mayon Volcano (Philippines) led to terrible destruction and the death of many thousands of people under lava flows.
In 1783, the Laki volcano exploded in Iceland, causing a drop in temperature that led to crop failure and famine in Europe in 1784.
And on the island of Sumbawa, who woke up in 1815, left on next year the entire Earth without summer, lowering global temperatures by 2.5 °C.
In 1991, a volcano in the Philippines also temporarily lowered it with its explosion, albeit by 0.5 °C.
A truly amazing sight is a volcanic eruption. But what is a volcano? How does a volcano erupt? Why do some of them spew out huge streams of lava at different intervals, while others sleep peacefully for centuries?
What is a volcano?
Externally, the volcano resembles a mountain. There is a geological fault inside it. In science, a volcano is a formation of geological rock located on the surface of the earth. Magma, which is very hot, erupts through it. It is magma that subsequently forms volcanic gases and rocks, as well as lava. Most of the volcanoes on earth were formed several centuries ago. Today, new volcanoes rarely appear on the planet. But this happens much less frequently than before.
How are volcanoes formed?
If we briefly explain the essence of the formation of a volcano, it will look like this. Under the earth's crust there is a special layer under strong pressure, consisting of molten rocks, it is called magma. If cracks suddenly begin to appear in the earth’s crust, then hills form on the surface of the earth. Through them, magma comes out under strong pressure. At the surface of the earth, it begins to break down into hot lava, which then solidifies, causing the volcanic mountain to become larger and larger. The emerging volcano becomes so vulnerable spot on the surface, which spews volcanic gases onto the surface with great frequency.
What is a volcano made of?
In order to understand how magma erupts, you need to know what a volcano is made of. Its main components are: a volcanic chamber, a vent and craters. What is a volcanic source? This is the place where magma is formed. But not everyone knows what a volcano’s crater and crater are? A vent is a special channel that connects the hearth with the surface of the earth. A crater is a small bowl-shaped depression on the surface of a volcano. Its size can reach several kilometers.
What is a volcanic eruption?
Magma is constantly under intense pressure. Therefore, there is a cloud of gases above it at any time. Gradually they push hot magma to the surface of the earth through the crater of the volcano. This is what causes an eruption. However, one small description the eruption process is not enough. To see this spectacle, you can use the video, which you need to watch after you have learned what the volcano is made of. In the same way, in the video you can find out which volcanoes do not exist nowadays and what the volcanoes that are active today look like.
Why are volcanoes dangerous?
Active volcanoes pose a danger for a number of reasons. The dormant volcano itself is very dangerous. It can “wake up” at any time and begin to erupt streams of lava, spreading over many kilometers. Therefore, you should not settle near such volcanoes. If an erupting volcano is located on an island, a dangerous phenomenon such as a tsunami may occur.
Despite their danger, volcanoes can serve humanity well.
How are volcanoes useful?
- During the eruption, a large amount of metals appears that can be used in industry.
- The volcano produces the strongest rocks that can be used for construction.
- Pumice, which appears as a result of the eruption, is used for industrial purposes, as well as in the production of stationery erasers and toothpaste.
August 18, 2016
Volcanic eruptions have always given rise to catastrophic associations in people's minds...
Boiling hot lava, vast clouds of volcanic ash eclipsing the Sun, dying people and entire cities are the subject of many paintings, books and films. Nowadays, volcanoes with a “bad reputation” that continue to erupt are popular among tourists, lovers thrills. We will tell you about the five most famous active volcanoes on Earth.
Vesuvius
On the conscience of this relatively low (1300 meters above sea level) volcano on the shores of the picturesque Bay of Naples are two destroyed ancient Roman cities, Pompeii and Herculaneum.
Vesuvius has erupted more than once in Italian memory, last time- in 1944. Eruptions were always accompanied by destruction and casualties; in 1805, the city of Naples was even destroyed. However, the area around the volcano is densely populated - volcanic ash fertilizes the land.
Krakatoa
The only known volcano that managed to be reborn after it destroyed itself. In 1883, the most destructive eruption in the history of mankind occurred at the Krakatoa volcano, located on the island of the same name between Java and Sumatra.
The tsunami wave washed away 295 Indonesian cities and villages into the sea, killing 35 thousand people. Both the island of Krakatoa and the volcano itself were destroyed. However, in 1927, the volcano broke through the ocean and declared itself with a new eruption. The new volcano was named Anak Krakatau, and it is believed that it has a serious impact on the climate of the entire Earth. The last activity of the Krakatoa volcano was observed in 2014.
Fujiyama
The Japanese have a peculiar attitude towards Fuji; they do not experience mortal horror, rather the opposite. Followers of the Shinto religion consider Fuji a shrine, a symbol of the immortality of the soul, and even built a temple on its top, next to the post office and meteorological station. Fuji, along with tourists from all over the world, is visited annually by thousands of Shinto pilgrims.
Hekla
Since then, about three dozen significant eruptions have occurred. All are completely different from one another and unpredictable. Some are short, a few days, others can last for months. And the eruption, which began in March 1947, ended only in April 1948. Icelanders believe that the longer the volcano’s “hibernation” lasts, the more catastrophic the consequences of the earthquake will be.
Klyuchevskaya Sopka
Outside the Caucasus, Klyuchevskaya Sopka is the most high mountain in Russia (4800 meters). And the highest active volcano on the Eurasian continent. Klyuchevskaya Sopka is the most active of Kamchatka's 29 active volcanoes; the last eruption occurred in 2013.
Despite the restless and unpredictable nature of the volcano, climbers and mountain tourists often climb Klyuchevskaya Sopka. The volcano also attracts tourists with an amazing natural phenomenon - lenticular clouds. Large white clouds hover over the crater of Klyuchevskaya Sopka and remain motionless even in very strong winds.
Publication date 08/10/2014 08:03
Each of us has heard a lot about volcanoes, some were even lucky enough to visit one of them, but most have a very superficial understanding of what a volcano is, what its nature is, how they arise and what their nature is. You will find everything about volcanoes in this article below about what volcanoes are, what they are like, what they are needed for.
What is a volcano?
Essentially, a volcano is a hole in the earth's crust. When a volcano erupts from the depths of the Earth to the surface, very hot molten rocks erupt through this hole. Volcanoes that are often active are called active. Volcanoes that may become active in the future are called dormant. An extinct volcano is a volcano whose activity has ceased forever.
Where are the volcanoes?
There are approximately 840 active volcanoes in the world. Typically, only 20-30 eruptions occur per year. Most volcanoes are located near the edges of the giant plates that together make up the outer layers of the Earth. An earthquake occurs every 30 seconds in the world, and only a few of them pose a real danger.
Structure of the volcano
For those who want to find out what the volcano is made of, we advise you to study the following images in detail and carefully:
What is the largest volcano in the world?
The largest volcano in the world is Mauna Loa in Hawaii in the USA, the dome of which is 120 km long and 50 km wide. Volcano Lo'ihi is an active volcano off the Hawaiian Islands. It goes under water for 900 m and will rise to the surface in the period from 10 thousand to 100 thousand years. You can see this volcano in the photo below:
What are high-speed waves called?
Speed waves are deep seismic waves traveling through the earth at a speed of 18 thousand km/h. They are much faster than sound.
What is the greatest lava flood?
In Iceland in 1783 there was a very strong fissure eruption. At the same time, the hot mass spread over a distance of 65-70 km.
When did people walk on the sea?
The Kat Mai volcano in Alaska, USA, erupted so much floating pumice in 1912 that people walked on the sea.
How many active volcanoes are there on earth?
There are currently approximately 1,300 active volcanoes on land. There are also many of them under water, but their number fluctuates, as some cease their activity, while others arise. Every dormant volcano can suddenly explode. Consequently, those volcanoes that have been active at least once over the past 10 thousand years are considered active.
What is a volcanic eruption?
Volcanic eruptions are a series of cannon-like explosions. They continue at intervals of hours and minutes, and occur as a result of the accumulation of a large volume of gas under the lava plug. During such eruptions, parts of the crater can fly off, the size of which can reach the size of a bus.
What is a Plinian eruption?
When the hot magma is saturated with gas and fills the volcano, its crater explodes, expelling it at a speed twice the speed of sound. The eruption is so strong that the magma breaks up into tiny pieces, and within a few hours the ground can be covered in a layer of ash. The eruption of Vesuvius in 79 had the same character. At the same time, the Roman writer Pliny could not escape, which is why this type of eruption is called Plinian.
What is the Stomboli eruption?
If the magma is liquid enough, a crust can form above the lava lake in the volcano's crater. At the same time, large bubbles of gas float out and explode the shell, splashing out volcanic bombs from semi-molten lava and fragments of lava rock. These types of eruptions are called strombolian eruptions from the Italian volcanic island of Stromboli.
What was the most powerful volcanic eruption?
The most powerful volcanic eruption occurred approximately 20 thousand years ago, when the Toba volcano raged on the island of Sumatra in Indonesia. A crater 100 km long formed in its center, and the other part of the island was buried under a layer of volcanic rock more than 300 m thick.
Why did Pompeii perish?
Throughout human history, volcanoes have been dangerous for people living near them. In 79 AD, the Roman city of Pompeii was razed to the ground by the erupting volcano Vesuvius. Even today, powerful eruptions can cause harm to people.
When did the legend of Atlantis originate?
Around 1645 BC. e. The Greek island of Santorini exploded. As a result, the Minoan civilization was destroyed. This fact served as the beginning of the legend of the missing continent of Atlantis.
Useful information about volcanoes, geysers, photos of volcanoes
The most dangerous and unpredictable objects on the earth's surface are volcanoes- geological formations that arise above cracks in the earth’s crust, through which hot magma, burning all living things in its path, erupts onto the earth, hot gases and rock fragments.
In this case, volcanoes are divided into active, dormant and extinct. Erupted magma is called lava. At times it slowly pours out of cracks, and at other times the volcano erupts with a strong explosion of steam, ash, dust and volcanic ash. It is these processes that lead to consequences that do not benefit people. Man today has no means to resist a volcanic eruption other than escape.
What are pyroclastic flows? When a volcano's crater is exposed, it breaks up the rocks and creates enormous amounts of debris, ash and pumice - pyroclastic materials. During eruptions, they are the first to rise up the vent. After the hole expands, magma begins to pour out of it. In this case, the pyroclastic cloud becomes so thick that it cannot mix with the air to rise upward. Because of this, it flows out in hot avalanches - pyroclastic flows that move at enormous speeds, reaching 200 km/h. They can cover large areas with eruption products.
What types of volcanoes are there?
In places where they diverge tectonic plates, magma flows through cracks, forming fissure volcanoes. Rapidly solidified thick lava forms mound volcanoes. During powerful volcanic eruptions, a caldera settles into the crater. Water often flows into it, and then a lake is formed. The most specific are stratovolcanoes, which are composed alternately of layers of lava and ash.
Lava erupting from focal and fissure volcanoes is usually fluid. As it cools, it creates basaltic rocks such as basalt, gabbro and dolerite. In situ it becomes rocks such as andesite, trachyte and rhyolite.
Formations from volcanic eruptions
Basalt columns. A dense flow of liquid lava, when hardened, can break into hexagonal basalt columns, reminiscent of those at the Great Dyke in Northern Ireland.
Pahoehoe lava. Sometimes rocks on the surface quickly harden, creating a thin crust over the still viscous and hot lava. If the crust is several centimeters thick, then it cools down to such an extent that you can walk on it. However, if the lava continues to flow, the crust begins to wrinkle. The Hawaiians nicknamed this lava “pahoehoe,” which means “wavy.”
Lava aa. If lava rapidly solidifies into a rough mass, it is called "aa". During underwater volcanic eruptions, such as at mid-ocean ridges, the water instantly cools and breaks the lava into small, smooth particles called “pillows.”
Focal volcanoes. Most volcanoes lie along crustal plate boundaries, as they sit above a single accumulation of magma flowing to the surface. Even when the plate moves, such a source continues to remain in place, burning and burning through it at various points, forming a chain of volcanoes.
What kind of lava can volcanoes have?
Volcanoes can erupt lava of two types: aa-lava And wavy lava.
Aa lava is thicker and petrifies with sharp rock fragments - volcanic scoria.
Wavy lava is lava that is more fluid and rich in gases. When hardened, it creates rocks with a smooth surface, and sometimes flows down to form long stalactites. Ash clouds emitted by volcanoes are lava powder.
How geysers appear
Hot springs and geysers are formed by boiling magma. When it leaks, rainwater seeps underground and encounters hot magma. Due to pressure, its temperature can increase, and then the magma will rise again. If when going up hot water mixed with cold water, it flows to the surface in the form of a hot spring. If it encounters an obstacle on its way, it remains under pressure and then splashes out in a strong stream called a geyser.
Eruption force
Some volcanoes can explode more powerfully than atomic bomb. As a rule, this happens if the magma thickens and becomes so viscous that it plugs the volcano's mouth. Inside it, the pressure gradually increases until the magma dislodges such a plug. The strength of eruptions is often measured by the amount of ash that is thrown into the air. As magma flows underground, it takes on various forms thanks to rocks. Typically, flowing magma flows into cracks within rocks, a process called conformable intrusion. In this case, saucer-shaped rocks are formed, such as lopoliths, lens-shaped ones - phacolites, or flat layers - sills. Viscous magma can push rock hard enough to create cracks, a process called unconformity intrusion.
Eruption forecast. How realistic?
It is extremely difficult to predict the time when the volcano will wake up. Eruptions in Hawaii are quite calm, frequent and relatively predictable, but most natural disasters are difficult to predict. A tiltmeter is used as one of the means to determine an upcoming eruption. It is a device for determining the steepness of the slopes of a volcano. If it increases, the magma located in the center of the volcano swells and an eruption may occur. But it should be remembered that such changes are only accurate shortly before the eruption, making this type of forecasting extremely dangerous.
