The Tonga Eruption and Volcanoes

Recently, the Hungo volcano on the Island of Tonga exploded, leaving thousands of people stranded and homeless. It was the most explosive eruption the world has seen in over 30 years, but what exactly caused it and how did it erupt?

Volcanoes are structures of rock or earth which are situated directly above large reserves of magma. They are present in many forms like calderas, volcanic craters and mountains; having existed on Earth for millions of years. They are classified into three types: Active, Dormant, and Extinct.

The magma from underneath a volcano constantly pushes up against the crust of the earth with a strong pressure called the magmastatic pressure, but the surface also pushes down on it with enough force to keep it trapped in, producing lithostatic pressure. Sometimes, the pressure build up is too great to be contained, and the volcano erupts, spewing magma, ash, and other gases into the atmosphere. Like this, the ground underneath the Tonga volcano was unable to bear the force of the magma and erupted. With its magnitude, it would have resulted in a huge loss of life but the island of Tonga was fortunately uninhabited. The eruption, however, caused powerful shockwaves and produced tsunamis with 15 metre high waves that could be felt as far as Peru in South America and Alaska in the North Pole.

Volcanic eruptions are generally measured in the Volcanic Explosivity Index (VEI). It measures the number of materials ejected from a volcano into the atmosphere, with the scale increasing logarithmically. Volcanoes are quite dangerous and can result in a huge loss of life, but their constructive effects cannot be overlooked. The materials they let out block out the sun's rays for a few weeks to months. This reduces the global temperature of the earth and cools a lot of the warm currents in the ocean. Volcanoes form new landforms and a lot of the craters of volcanic eruptions are now huge lakes that support a variety of landforms. Perhaps the most important effect is that most of the gases in our atmosphere were indirectly produced by volcanoes. Millions of years ago, volcanic eruptions were much more common than they are today. The gases emitted by them were used by the first living plants to produce oxygen that is so abundant today.

Volcanoes are very interesting and they are being studied by volcanologists in detail for better ways to predict and understand them. Volcanoes remain a learning experience for those who study them and all mankind. The impact of Hungo may have been heard at the moment, but its impact will become part of history.