The relative amount of volcanic activity is something of a disputed subject at the moment. On the one hand charts, such as the one below, argue we are seeing a rapid increase in the amount of activity. However, others argue that widespread modern scientific monitoring, expanding population observation and worldwide communications have improved recording, reporting and awareness rather than pointing to an increase in activity.
What do we know?
There are circa 1500 volcanoes on the planet with 73 having erupted in 2019 up from 71 in 2017 with 20 – 40 erupting at any one time. Note these figures do not include most eruptions (which occur) on the deep sea floor. Estimates of global magna budgets (the amount of lava released from the Earth) suggests that roughly 75% of the lava reaching Earth’s surface does so unnoticed at submarine mid-ocean ridges. Some estimates give the number of young seafloor volcanoes as exceeding one million.
The massive Mid-Ocean Ridge system wraps around the globe like a seam on a baseball, stretching 65,000 kilometres (40,390 miles). The majority of the system is underwater, with an average water depth to the top of the ridge of 2,500 meters (8,200 feet).
Mid-ocean ridges are geologically important because they occur along divergent plate boundaries, where new ocean floor is created as the Earth’s tectonic plates spread apart. As the plates separate, some molten rock rises to the seafloor, producing enormous volcanic eruptions of basalt, and building the longest chain of volcanoes in the world. Because most of these eruptions occur deep under the water, they often go unnoticed.
One factor likely to affect the amount of future volcanic activity is global warming.
A 2017 study published in the ‘Geology’ journal researched a link between melting glaciers and ice caps and an increase in volcanic activity. Looking at a period of cooling about 5,500 years ago in Iceland, the researchers found that growing ice coverage coincided with a decrease in eruptions. The same was true in reverse: when the ice retreated, the number of eruptions increased.
As the world’s ice sheets shrink and glaciers melt, it has been suggested the retreat could usher in a new era of volcanic activity.
What of ‘Super Volcanoes’?
A Super Volcano by definition is one which has had an eruption of magnitude 8 – the highest and most violent possible – on the Volcano Explosivity Index in the past.
The US is a hotspot for super volcanoes, with four currently located in North America, while Europe only has the one – but it is one which could destroy the continent.
Despite all our knowledge and attempts at predicting when and where the next eruption will occur, Clive Oppenheimer, professor of volcanology at the University of Cambridge, says “Of course, [the next big eruption] is likely to be in a volcanic region that we already know about. But I think one of the lessons of history, even recent history, is the really big eruptions have not happened at volcanoes that scientists were looking at”.
What does this mean?
Whether we are presently seeing an increase in volcanic activity or not, it is certain that we will.
Micah 1: 3-4– ‘Look! The Lord is coming from his dwelling place; he comes down and treads on the heights of the earth. The mountains melt beneath him and the valleys split apart, like wax before the fire, like water rushing down a slope.’ (NIV) – the later describing pyroclastic flow?
Nahum 1: 5-6– ‘The mountains quake before him and the hills melt away. The earth trembles at his presence, the world and all who live in it. Who can withstand his indignation? Who can endure his fierce anger? His wrath is poured out like fire; the rocks are shattered before him.’ (NIV)
These passages, so vividly describing, still future, devastating global volcanic activity, were written nearly 3,000 years ago, long before we had the knowledge we now have, long before widespread monitoring and recording and global sharing of information, long before we had explored the nations or the oceans thus long before we knew the Earth contained the number and global spread of volcanoes needed to bring about what is described.
What else does the Bible tell us?– The Future
What does that mean for you?– Good News
Sunday Express 17thAugust 2018