Things Yoram knows: what calms the volcanoes?

Naama Erzi asks: Why do volcanoes stop being active?

We all know that between eruptions of a volcano there are rest periods and in the end the volcano goes silent for good. but why? If a balloon is punctured the burst of air will continue until the balloon is deflated so why wouldn't black in the earth's crust behave similarly?

So it's a shame that the earth is not like an inflated balloon, under the thin crust we live on magma flows: rock in a liquid state and liquids tend to stay in the container they are in as long as they are not pushed away. In at least two cases: one in Iceland and one in Hawaii, deep drilling hit a magma chamber without causing any eruption. What causes lava to erupt (lava is magma that has reached the surface) is the pressure of gases. When you open a bottle of carbonated drink, you hear and see a gas coming out, which sometimes sweeps some of the liquid away with it. A similar phenomenon occurs in magma climbing up a crack in the rocky crust. Gases that were dissolved come out of the liquid and break out. Some of these gases are dissolved in the magma, for example sulfur oxides, but most of the gas is simply steam, the result of the meeting between the molten rock and water that seeps deep into the earth. In an eruption, the gases are released, the pressure drops, and after that the mountain will be quiet until the next time when enough pressure is created in the magma cells at the bottom.

But this cycle doesn't last forever: every volcano eventually fades.

The Earth is covered in a solid layer that is several tens of kilometers thick and consists of several plates that move slowly on the liquid below. Most of the volcanoes are in the seam zones between the plates. Magma climbs in the gaps that open in the seam, creating pockets of molten material (magma cell) that cools slowly and forms granite rocks or gas pressure causes it to erupt quickly and form the basalt rocks. Other volcanoes form at a weak point within a plate such as the one that creates the famous geysers of Yellowstone and the Hawaiian Islands.

Volcanoes go out and others are created all the time

Since the plates that make up the earth's crust are in motion, the points where the magma can climb up also move. New volcanoes are formed and others are extinguished forever. A "hot spot" meaning a crack through which magma flows created the island state of Hawaii in the Pacific Ocean. The hot spot is under a tectonic plate moving towards the northwest so that the large island where there is volcanic activity is the southeast and the row of extinct islands to the northwest is a kind of trace map showing the progress of the plate in the last 5 million years.

The islands where the volcano is not active are slowly disappearing through processes of erosion and weathering into the ocean. The energy for all this activity is heat generated deep in the earth from the decay of radioactive elements (mainly uranium and potassium). And so it is natural to ask: what will happen to the earth when this source of energy runs out and the tectonic and volcanic activity stops? Our surface is determined by two forces: the movement of the rock plates that creases the landscape: lifts mountain ranges and creates deep chasms below sea level and the activity of the atmosphere that irons the world: sweeps away the uplifted land and fills the fissures.

Stopping underground activity is supposed to create a flat world. The Himalayas, the Alps and the Andes will be slowly washed into the ocean, the Mariana Trench will be filled with dirt and the sphere will reach a stable and smooth state: a sea with a uniform depth of about 2 kilometers. But that's not what we really expect.

When the magma cools and solidifies and the currents in it are stopped, the earth will lose the dynamo that creates its magnetic field. Mars, smaller than Earth It's enough to get to this point - It is completely solid and does not have a magnetic field that will keep the flow of particles from the sun away from it. The lighter the particle, the greater the chance that the solar wind will blow it into space, and the lightest and most sensitive atom is hydrogen, which forms water with oxygen. Mars and Venus, lacking the magnetic field, lost the water they had except for remnants of glaciers protected from the solar wind below the surface of Mars.

According to a model based on the analysis of traces of ancient magnetism in zircon crystals in rocks, the age of the magnetic field and the beginning of the earth's plate tectonics is about 3 billion years and the magnetic field is getting weaker as the earth cools. According to this model, the movement of the plates will stop and with it the magnetic field will disappear in about 1.4 billion years. When the sphere is exposed to what the sun flows into it, our world will lose water and therefore weathering and erosion will stop. As in Mars there mMount the extinct volcano Olympus To a height of 22 kilometers, the mountains will also add a view to an arid and still landscape that will wait patiently to the last stage in the evolution of our sun In it she will swell and swallow the planets next to her and our world inside them.

Did an interesting, intriguing, strange, delusional or funny question occur to you? sent to ysorek@gmail.com

More of the topic in Hayadan:

• Assessment: Huge emissions of C02 from volcanic activity caused a mass extinction of species about 200 million years ago
• A volcanic eruption caused the creation of an island near Japan (watch the video)
• The volcanic ash from the third eruption of the volcano in Iceland will not endanger aviation in the country