The melting temperature of concrete is around 1,500 degrees Celsius, significantly higher than the temperature of magma, which is about 871 degrees Celsius. So, can concrete be used to seal the mouth of a volcano?
Every year, 20 billion tons of concrete are used, making it the most widely used material in the world. This material is also incredibly durable; the Colosseum, a famous marvel in Italy, has stood strong for nearly 2,000 years and was built using concrete.
Concrete is made from gravel, water, and a small amount of cement. The strongest concrete in the world can withstand the pressure found in the Challenger Deep, the deepest part of the ocean.
Volcanic eruptions are associated with heat and increased magma pressure. The pressure differential between the surface and magma is proportional to the eruptive force of a volcano.
Strong pressure can also cause the concrete plug to shatter.
If a concrete plug is placed over a volcano’s mouth, it will significantly increase the pressure beneath the surface compared to normal levels. This could lead to a more powerful eruption, as magma will force its way out from the sides of the volcano if it cannot penetrate through the concrete.
This phenomenon occurred in 1980 when Mount St. Helens erupted. A fissure on the side of St. Helens was created due to an earthquake’s impact, causing St. Helens to erupt horizontally instead of vertically. The materials ejected from the eruption reached speeds of up to 350 m/s.
Furthermore, strong pressure can also cause the concrete plug to shatter. Dust from concrete in the air poses risks of lung disease and cancer.
Lava flows from a natural eruption are typically slow and predictable, so concrete should only be used to redirect lava flows away from populated areas.
