The eruption of the volcano is one of the most spectacular sights. Only a few people see the true and uncontrollable power of nature with their own eyes. Most of the inhabitants of the earth observe this in films and video materials. But no one can imagine what actually happens at this moment in the epicenter of the eruption.
According to geologists, there are about 1,500 active volcanoes on Earth. During eruptions, many geological processes take place at the epicenter, and not just the release of lava and the rise of a column of hot ash into the air. At the same time, local tectonic changes can occur at the base of the formations, often lava cavities or natural pipelines are formed.
Lava-lined giant cavities.
How lava cavities form
Lava tubes create amazing landscapes, surface grottoes, long caves, which, after fading, become a natural treasure.
They are formed in solidified lava flows directly during the eruption of molten mineral mass. Lava, flowing down the slopes from the mouth of the volcano, gradually cools and thickens. Cooling starts from the upper layers during the contact of the outer layer with air. This layer hardens to form a strong mineral crust. The shell becomes a kind of heat insulator and protects internal flows from solidification and rapid cooling.
Solidified lava, under which natural pipelines are formed.
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Hot lava flows further under the shell. It melts the earth's rock, so the gaps are quite spacious and decrease only after hundreds of meters. And only after the masses have completely cooled, the exits are clogged. Sometimes the lower hotter streams find another passage and begin to flow in a new direction. Then the pipelines have a branched system.
If the flowing mass reaches the reservoir, beautiful grottoes are formed, partially filled with water.
Conditions for creating natural pipelines
The formation of cavities occurs under certain conditions:
- the slope angle should not exceed 5 degrees;
- the slopes of the volcano should be gentle and uniform;
- the optimum temperature of the longwall at the outlet should be at least 1200 ° C, then it will be less viscous.
Entrance to lava cavities in Kamchatka.
If these characteristics of the medium are observed, the flow rate in the pipes can reach 60 km / h. Then the height of the grottoes can reach 20 meters, gradually decreasing to 1 meter, and then there is a sharp clogging. The caves in this case will be extended, with a mass of picturesque halls and branches.
Famous lava formations on the planet
The most picturesque cavities formed by volcanic activity are found in Hawaii. Here, in the lava flows of the Kilauea volcano, is the largest Kazumura cave. Its study began about 50 years ago after the discovery of a gigantic failure. During this time, research teams have found dozens of branches stretched over 65.5 km, located at a depth of over 1 km. The sleeves are connected in an extensive network, which can be bypassed in only a few days.
Kazumura cave.
No less amazing in terms of geography is the whole Jeju Island, 400 km from Seoul. Its origin is associated with the activity of an underwater volcano, which for a long time seethed and boiled overlapping streams. They formed many tunnels, formed into several deep systems. The largest is considered to be Manjangul. It stretches for 13 km, the most voluminous tunnels reach 30 meters in height.
Manjangul cave.
Of course, most of the caves are hidden from the eyes of tourists. Geologists are preparing the safest and most scenic stretches of giant natural pipelines to visit. But this is enough to enjoy the greatness of nature and admire the picturesque vaults.
Whether lava cavities can become a refuge for people in the event of global cataclysms, see the video.