More than 109,000 lightnings hit before deadly White Island volcanic eruption in New Zealand. Picture: Small eruption of Mount Rinjani, with volcanic lightning by Oliver Spalt / CC BY 2.0 via WikipediaIn the 24 hours leading up to 7am on December 7, 2019, 109,000 lightning strikes were recorded over New Zealand and its surrounding waters, with 18,000 over the land.
Previously the records had only seen 44,000 strikes over both land and sea. That’s an amazing 65,000 more!
What Causes Volcanic Eruptions?
About 1 day after, on December 8, 2019, White Island volcano, situated on New Zealand’s South island, erupted, killing at least 5 people.
There are different causes for a volcano to erupt.
All fundamentally come down to a pressure change within the volcano which ejects the magma from its chamber beneath the volcano.
The most common type of eruption is caused by the movement of tectonic plates.
When one is pushed under the other the magma, sediment and seawater is forced into the chamber which eventually overflows and the volcano erupts spewing lava into the sky.
This kind of eruption produces sticky, thick lava at temperatures from 800 to 1,000°C.
The second type of eruption caused by tectonic plates is when the plates move away from each other allowing magma to rise and fill the the gap.
Such events can cause a gentle explosion of thin lava of temperatures between 800 to 1,200°C.
Decreasing temperatures can cause old magma to crystallise and sink to the bottom of the chamber and this movement can force fresh liquid magma up and out – similar to dropping a brick in a bucket of water.
- Decrease External Pressure
Finally a decrease in external pressure can trigger an eruption as it may minimize the volcano’s ability to hold back by increasing the pressures inside the magma chamber.
This kind of eruption can be caused by natural events such as strong thunderstorms, hurricanes, typhoons, which decrease rock density as well as snow melting – one cause behind the 2010 Eyjafjallajökull eruption in Iceland.
White Island Eruption Linked to Thunderstorms?
Strong thunderstorms engulfed New Zealand and its South Island with more than 109,000 lightnings on Saturday:
On Sunday, more than 300,000 lightnings:
In overall, more than 857,000 lightning bolts hit New Zealand in less than 72 hours (midnight Friday):
The lightnings may have not played a big role in triggering the deadly White Island volcanic eruption.
But the magma coming up to the surface may have changed the electrical field of the entire area, causing the storms and lightning strikes to appear.
And those powerful and extremelly low-pressure thunderstorms that swept across the region, may have changed the pressure inside the volcano magma chamber and thus initiate the eruption. What do you think about this theory?