Introduction
- A volcano is a crack in the crust of a planet, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber beneath the surface. Volcanism is a process that has been occurring on Earth since the early stages of its evolution over 4 billion years ago.
- After 38 years, the world’s largest active volcano, Mauna Loa, erupted, spewing ash and debris.
Body
A volcanic eruption’s process
- The deeper one goes beneath the Earth’s surface, the hotter it becomes.
- A geothermal gradient is the amount by which the temperature of the Earth increases with depth.
- A geothermal gradient is the flow of heat from the Earth’s warm interior to its surface.
- At a certain depth, this heat begins to melt the rocks, resulting in what geologists refer to as’magma.’
- Because magma is lighter than solid rock, it rises and collects in magma chambers.
- These magma chambers, which are found at a relatively shallow depth of 6-10 km below the surface, have the potential to cause volcanic eruptions.
- As magma accumulates in these chambers, it forces its way up through cracks and fissures in the Earth’s crust, causing volcanic eruption.
- Lava refers to the magma that surfaces on the Earth’s crust; this lava can be explosive at times.
- Chambers with the potential to cause volcanic eruptions are found at a relatively shallow depth of six to ten kilometres below the surface.
- As magma accumulates in these chambers, it pushes its way through cracks and fissures in the Earth’s crust. This is referred to as a volcanic eruption. Lava is the name given to magma that rises to the surface of the Earth’s crust.
Hawaiian volcanoes are distinct from other volcanoes.
- The majority of the world’s volcanoes form along the boundaries of Earth’s tectonic plates, which are massive expanses of our planet’s lithosphere that constantly shift and collide.
- When two tectonic plates collide, one often sinks deep beneath the other, creating a subduction zone.
- Temperatures and pressures rise as the descending landmass sinks deeper into the Earth, releasing water from the rocks.
- The water slightly lowers the melting point of the overlying rock, resulting in magma that can rise to the surface—the spark of life that can reawaken a dormant volcano.
- Not all volcanoes are caused by subduction. Another type of volcano formation is known as hotspot volcanism.
- In this case, a hotspot of magmatic activity in the middle of a tectonic plate can push up through the crust and form a volcano.
- Although the hotspot itself is thought to be mostly stationary, the tectonic plates continue their slow march to the surface, forming a line of volcanoes or islands. This mechanism is thought to be the driving force behind the Hawaiian volcanic chain.
Reasons for the explosive nature of some eruptions
- Runny magma produces less explosive volcanic eruptions, which are typically less dangerous.
- Because the magma is runny, gases can escape, resulting in a steady but relatively gentle flow of lava from the volcano’s mouth. This is the type of eruption that occurred at Mauna Loa.
- Thick and sticky magma makes it difficult for gases to escape consistently. This causes pressure to build up until a breaking point is reached.
- At this point, the gases all escape violently and simultaneously, resulting in an explosion.
- Lava blasts into the air, breaking up into tephra-like fragments. Mount Vesuvius, which destroyed Pompeii, is an example of an explosive volcano.
Conclusion
As urbanisation and globalisation increase, volcanoes have a greater impact on man and material. The effects have an impact on flora, fauna, and global warming, which can hasten climate change.
Legacy Editor Changed status to publish December 7, 2022