Video: Know more about volcanoes and how they erupt

 

Thousands fled from their homes as lava oozed out of a Mayon, a rumbling Philippine volcano on Monday, January 15, 2018, in what volcanologists described as a “quiet eruption”, warning it could lead to a hazardous explosion within days.

But what leads to volcanic eruptions?

Most of the world’s volcanoes are found around the Pacific Ocean’s Ring of Fire, a meeting point of tectonic plates and an area of intense seismic activity.

Tectonic plates are massive slabs of rock making up the Earth’s surface. Constantly moving on a hot bed of magma, volcanoes form in two ways at their boundaries.

Plates sometimes collide, causing one to slide beneath the other. This is called a destructive boundary.

Pressure and heat created by this movement forces magma up into cracks in the rocks until it explodes to the surface, as lava, causing a volcanic eruption.

Molten rock, debris and gases from the Earth’s interior are also emitted – either from the main crater or from secondary vents.

Plates can also move away from each other at so-called constructive boundaries.

In this case magma rises to fill the gap, creating a new crust. When this happens under the sea volcanic islands are eventually formed.

Volcanic activity can also occur underneath tectonic plates – in areas known as hot spots – when magma escapes through localized melted molten rock.

In terms of activity volcanoes are:
– Extinct, when they haven’t erupted for tens of thousands of years
– Dormant, when they are temporarily inert
– Active when they regularly churn out gas or lava

Sources: National Geographic, USGS

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