Why is the water in the geyser hot? Even if a huge stream of water did not shoot into the air from the geyser, it would still remain one of the most interesting wonders of nature. A geyser is truly a hot spring, and a hot spring is itself

Why is the earth hot inside? Outer thickness earth's crust in different places it ranges from 15 to 50 km, and its temperature increases as it approaches the center of the Earth. Approximately every 40 m it increases by one degree. It's so hot at a depth of three kilometers

HOT WASH A bi-weekly magazine of satire and humor. The only issue was published on October 31, 1934 in Gorky. Publication of the newspaper “On Ilyich’s Rails” of the political department of the 4th branch of the Moscow-Kursk railway. Responsible editor - A. V. Shuklin. Printed on 8 pages, with

Chapter Six REAL DANGERS OF WATERIn previous chapters, some objectively difficult and potentially dangerous situations: diving in an unfamiliar place; the fatal role of alcohol in accidents on the water; jellyfish - “cross-shaped” jellyfish that live in Pacific Ocean;

Why is the water in the geyser hot? Even if a huge stream of water did not shoot into the air from the geyser, it would still remain one of the most interesting wonders of nature. A geyser is truly a hot spring, and a hot spring is itself

Volcanic lava is called the blood of the Earth. It is an integral companion of eruptions and each volcano has its own composition, color and temperature.

1. Lava is magma that flows out of a volcanic vent during an eruption. Unlike magma, it does not contain gases, since they escape during explosions.

2. Lava began to be called “lava” only after the eruption of Vesuvius in 1737. Geologist Francesco Serao, who was researching the volcano in those years, initially called it “labes”, which means “collapse” in Latin, and later the word acquired its modern meaning.

3. Different volcanoes have different lava compositions. Most often it is composed of basalts and differs slow flow, like batter.

Basaltic lava at Kilauea Volcano

4. The most liquid lava, resembling water, contains potassium carbonates and is found only on.

5. In the depths of the Yellowstone supervolcano there is rhyolite magma, which has an explosive nature.

6. The most dangerous lava is corium, or lava-like fuel contained in nuclear reactors. It is a fusion of the contents of the reactor with concrete, metal parts and other debris that is generated as a result of a nuclear crisis.

7. Despite the fact that corium has a technical origin, its flows are under Chernobyl nuclear power plant outwardly resemble cooled basalt flows.

8. The most unusual in the world is the so-called “blue lava” on the Ijen volcano in Indonesia. In fact, the brightly glowing streams are not lava, but sulfur dioxide, which, when exiting the ventilation holes, turns into liquid state and shines with blue light.

9. You can determine its temperature by the color of lava. Yellow and bright orange are considered the hottest and have a temperature of 1000 °C and above. Dark red is relatively cool, with temperatures ranging from 650 to 800 °C.

10. The only black lava is found in the Tanzanian volcano Ol Doinyo Lengai. As mentioned above, it consists of carbonates, which give it a dark tint. The lava flows at the summit are quite cool - with a temperature of no more than 540 °C. When cooled, they become silvery in color, creating bizarre landscapes around the volcano.

11. On the Pacific Ring of Fire, volcanoes erupt mainly silicon lava, which has a viscous consistency and solidifies in the mouth of the mountain, stopping its eruption. Subsequently, under pressure, the frozen plug is knocked out of the crater, resulting in a powerful explosion.

12. According to research, in the early days of its existence, our planet was covered with lava oceans, layered in structure.

13. When lava flows down slopes, it cools unevenly, so sometimes lava tubes form inside the flows. The length of these tubes can reach several kilometers, and the width inside is 14–15 meters.

» » Cooling of lava

The time required for lava to cool cannot be determined precisely: depending on the power of the flow, the structure of the lava and the degree of initial heat, it varies greatly. In some cases, lava hardens extremely quickly; for example, one of the flows of Vesuvius froze in 1832 in two months. In other cases, lavas are in motion for up to two years; often, after several years, the temperature of the lava remains extremely high: a piece of wood stuck into it instantly catches fire. This was, for example, the lava of Vesuvius in 1876, four years after the eruption; in 1878 it had already cooled down.

Some streams form fumaroles over many years. At Jorullo, in Mexico, in the springs passing through the lava that poured out 46 years ago, Humboldt observed a temperature of 54°. Flows of significant power freeze even longer. Skaptar-jokul in Iceland in 1783 identified two lava flows, the volume of which exceeded that of Motzblanc; It is not surprising that such a powerful mass solidified gradually over the course of about a century.

We have seen that lava flows quickly solidify from the surface and are covered with a hard crust, in which the liquid mass moves, as if in a pipe. If after this the amount of lava released decreases, then such a pipe will not be completely filled with it: the upper cover will gradually sink, stronger in the middle and less at the edges; Instead of the usual convex surface, which is represented by any thick fluid mass, you get a concave surface in the form of a trench. However, the hard crust covering the stream does not always sink: if it is powerful and strong enough, it will withstand its own weight; in such cases, voids form inside the frozen flow; no doubt this is how the famous grottoes of Iceland arose. The most famous among them is Surtshellir (“Black Cave”) near Kalmanstung, located among a huge lava field; its length is 1600 m, width 16-18 m and height 11 - 12 m. It consists of a main hall with a number of side chambers. The walls of the grotto are covered with glassy shiny formations, magnificent lava stalactites descend from the ceiling; Long stripes are visible on the sides - traces of a moving fiery liquid mass. Many lava flows on the island of Hawaii are cut through by long grottoes, like tunnels: in some places these grottoes are very narrow, sometimes they widen up to 20 m and form vast high halls decorated with stalactites; they sometimes stretch for many kilometers and twist, following all directions of the lava flow. Similar tunnels have also been described on the volcanic islands of Bourbon (Reunion) and Amsterdam.

The question of what lava is has been of interest to many scientists for a long time. The composition of this substance, as well as its shape, speed of movement, temperature and other aspects have become the subject of a number of studies and scientific works. This can be explained by the fact that it is its frozen flows that represent almost the only source of information regarding the state of the Earth’s interior.

General concept

First, you need to figure out what lava is in the modern sense? Scientists call it the material in a molten state located in the upper part of the mantle. While in the bowels of the earth, the composition of the substance is homogeneous, but as soon as it approaches the surface, the process of boiling begins with the release of gas bubbles. They are the ones who move the hot material towards the cracks in the bark. However, not all of the liquid erupts to the surface. Speaking about the meaning of the word “lava”, it should be noted that this concept applies only to the spilled part of the matter.

Basalt lava

The most common type on our planet is basaltic lava. Most of all geological processes, which occurred on Earth many thousands of years ago, were accompanied by numerous eruptions of this particular type of hot substance. After it solidified, a black rock of the same name was formed. Half of the composition of basaltic lavas is magnesium, iron and some other metals. Due to them, the melt temperature reaches about 1200 degrees. At the same time, the lava flow moves at a speed of about 2 meters per second, which is comparable to a running person. As studies show, in the future they move much faster in the so-called “hot pursuit”. Basaltic lava from the volcano is thin. It flows quite far (up to several tens of kilometers from the crater). It should be noted that this variety characteristic of both land and ocean.

Acidic lava

In the case when the substance contains 63% or more silica, it is called acidic lava. The heated material is very viscous and practically incapable of flow. The speed of the flow often does not even reach several meters per day. The temperature of the substance is in the range from 800 to 900 degrees. Melts of this kind are associated with the formation of unusual rocks(ignimbrites, for example). If acidic lava becomes highly saturated with gas, it boils and becomes mobile. After being ejected from the crater, it quickly flows back into the resulting depression (caldera). The consequence of this is the appearance of pumice - an ultra-light material whose density is less than that of water.

Carbonate lava

Speaking about what lava is, many scientists still cannot determine the principle of formation of its carbonate variety. This substance also contains sodium. It erupts from only one volcano on the planet - Oldoinyo Lengai, which is located in Northern Tanzania. Carbonate lava is the most liquid and coldest of all existing species. Its temperature is approximately 510 degrees, and it moves along the slopes at the same speed as water. Initially, the substance has a dark brown or black color, but after just a few hours of being on the outside it becomes lighter, and after a few months it turns completely white.

Conclusions

To summarize, we should focus on the fact that one of the most pressing geological problems is associated with lava. It lies in the fact that this substance heats up the bowels of the earth. Pockets of hot material rise to earth's surface, after which they melt it and form volcanoes. Even the world's leading scientists cannot give a clear answer to the question of what lava is. At the same time, we can say for sure that it is only a tiny part global process, driving force which is hidden very deep underground.

When volcanoes erupt, hot molten rocks - magma - pour out. In air, the pressure drops sharply, and the magma boils - gases leave it.


The melt begins to cool. In fact, only these two properties – temperature and “carbonation” – distinguish lava from magma. Over the course of a year, 4 km³ of lava spills across our planet, mainly at the bottom of the oceans. Not so much, on land there were regions filled with a lava layer 2 km thick.

The initial temperature of the lava is 700–1200°C and higher. Dozens of minerals and rocks are melted in it. They include almost all known chemical elements, but most of all silicon, oxygen, magnesium, iron, aluminum.

Depending on the temperature and composition, lava can be different colors, viscosity and fluidity. Hot, it's shiny bright yellow and orange; cooling down, it turns red and then black. It happens that blue lights of burning sulfur run above the lava flow. And one of the volcanoes in Tanzania erupts black lava, which, when frozen, becomes like chalk - whitish, soft and brittle.

The flow of viscous lava is slow and flows barely (a few centimeters or meters per hour). Along the way, hardening blocks are formed in it. They slow down traffic even more. This kind of lava solidifies in mounds. But the absence of silicon dioxide (quartz) in lava makes it very liquid. It quickly covers vast fields, forms lava lakes, rivers with a flat surface, and even “lava falls” on cliffs. There are few pores in such lava, since gas bubbles easily leave it.

What happens when lava cools?

As the lava cools, the molten minerals begin to form crystals. The result is a mass of compressed grains of quartz, mica and others. They can be large (granite) or small (basalt). If cooling proceeds very quickly, a homogeneous mass is obtained, similar to black or dark greenish glass (obsidian).


Gas bubbles often leave many small cavities in viscous lava; This is how pumice is formed. Different layers of cooling lava flow down the slopes with at different speeds. Therefore, long, wide voids are formed inside the flow. The length of such tunnels sometimes reaches 15 km.

Slowly cooling lava forms a hard crust on the surface. It immediately slows down the cooling of the mass lying below, and the lava continues to move. In general, cooling depends on the massiveness of the lava, initial heating and composition. There are known cases when, even after several years (!), lava still continued to crawl and ignited branches stuck into it. Two massive lava flows in Iceland remained warm centuries after the eruption.

Lava from underwater volcanoes usually hardens in the form of massive “pillows”. Due to rapid cooling, a strong crust forms on their surface very quickly, and sometimes gases rupture them from the inside. The fragments scatter over a distance of several meters.

Why is lava dangerous for people?

Main danger lava - her high temperature. It literally burns living beings and buildings along the way. Living things die without even coming into contact with it, from the heat with which it radiates. True, high viscosity inhibits the flow rate, allowing people to escape and preserve valuables.

But liquid lava... It moves quickly and can cut off the path to salvation. In 1977, during the night eruption of Mount Nyiragongo in Central Africa. The explosion split the crater wall, and lava gushed out in a wide stream. Very fluid, it rushed at a speed of 17 meters per second (!) and destroyed several sleeping villages with hundreds of inhabitants.

The damaging effect of lava is aggravated by the fact that it often carries clouds of toxic gases released from it, a thick layer of ash and stones. It was this kind of flow that destroyed the ancient Roman cities of Pompeii and Herculaneum. A meeting of hot lava with a body of water can result in a disaster - the instantaneous evaporation of a mass of water causes an explosion.


Deep cracks and gaps form in the flows, so you need to walk on cold lava carefully. Especially if it is glassy - sharp edges and debris hurt painfully. Fragments of cooling underwater “pillows” described above can also injure overly curious divers.