What Happens to Lava After It Erupts from a Volcano

Volcanoes are some of the most spectacular natural phenomena on earth. During the eruption, they can hurl rocks, ash, and other debris up to a distance of several miles. Often, larger fragments fall back where they originated and create cinder cones or horned peaks. Yet that’s not the end of it for lava once it is released from the volcano—what happens to it after the eruption? 

To understand what happens to lava after it erupts from a volcano, we need to first understand where volcanoes get their lava from in the first place. Volcanic eruptions occur when pressure builds up inside a volcano so much that its walls cannot contain all of its magma anymore. This causes an explosive release of steam and volcanic gasses called magmatic volatiles, as well as a molten rock (lava) which then flows out in streams known as lavascapes.

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What Happens to Lava After It Erupts from a Volcano?

After the eruption, the lava cools and hardens. This process can take anywhere from a few days to a few years, depending on the type of lava and its cooling environment. The rate of cooling can be influenced by several factors, including the thickness of the lava flow, the surrounding air temperature, and the availability of water. 

If a lava flow is thick and there is little air circulation, it will cool slowly, forming a smooth, hardened crust. When thinner lava flows are exposed to air, they cool more rapidly and form a rough, cinder-like surface. The thickness of the cooling crust determines what happens next to the lava.

Depending on conditions, it can travel over land, underwater, or even through the atmosphere. Overland, lava flows can be very fast-moving, as they are not held back by gravity as much as water. They can also be highly destructive, as they can move over and destroy anything in their way. Overwater, lava travels more slowly and is more prone to cooling and solidification. When lava enters the ocean, it forms new land in the form of an underwater volcano called a ‘seamount.’

Residual Atmosphere and Residue

As lava cools after an eruption, it forms a residue containing gases and minerals that were inside the magma before it erupted. This residue can include water vapor, gases such as carbon dioxide, sulfur dioxide, hydrogen sulfide, and hydrogen, and minerals such as halite, calcite, and pyroxene. 

These substances can leave behind a trace of what the lava was made from. This atmosphere and residue are what cause the lava to solidify into hardened rock and create volcanic ash or dust.

Volcanic Ash and Dust

Volcanic ash refers to tiny fragments of rock and minerals produced by volcanic eruptions. These are too small to be called ‘sand’ but too big to be called ‘fines.’ Volcanic ash can be flying through the air and settle many miles away from the eruption site. Volcanic ash is often grey or black in color, but it can also be brown, red, yellow, orange, or even blue. These colors happen due to trace elements in the minerals that make up the ash, such as iron, titanium, and manganese.

As lava turns to ash or dust, it is carried by winds and can travel great distances. This is what causes a lot of damage, as it can be transported to places far from the eruption itself, including nearby towns and cities. If the eruption occurs in an area that has a lot of vegetation, this can cause fires to break out, spreading more ash and dust across even more areas. 

Volcanic ash is often very dangerous, as it can cause harmful breathing conditions in humans and animals, including lung and eye irritation, as well as respiratory issues.

Lava Rock Formation

As lava cools, it turns into rock if it is thick enough. Depending on the type of lava, it can take from days to thousands of years for it to cool and become solid rock. Lava rock formations occur when lava cools slowly, such as in areas where there are thick lava flows or where there is little movement, such as at the ocean’s edge, where there is no wind to carry it away. 

Lava rock formations can be either porous or non-porous. A porous lava rock formation is when the lava cooled slowly and has many holes inside of it, creating a sponge-like consistency. A non-porous lava rock formation is when the lava cooled quickly and has no holes inside of it.

Crater Formation and Scenery Change

As more and more lava is released over time, it can create a crater and change the scenery of the volcano’s surrounding area. As more lava is released over time, it piles up on top of the older lava, creating a larger and larger pile. When the pile of lava reaches a critical mass, it either collapses or erodes away, falling back to the ground as smaller pieces of lava. 

The areas in which lava falls back to the ground are where craters are formed. The more lava that falls back to the ground, the larger the crater becomes, and the more the surrounding area is changed.


The life cycle of lava is incredibly fascinating. After erupting from a volcano, the lava cools and hardens into rock, forming new landforms and changing the scenery nearby. These landforms can range from smooth, hardened lava flows to jagged, cinder-like lava. Lava rock formations are often porous and can be very dangerous if they are found near human settlements. 

Lava eruptions are some of the most spectacular natural phenomena on earth, but their effects can be destructive if they are not controlled. After an eruption, the lava cools and hardens into rock, forming new landforms and changing the scenery of the surrounding area.

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