What Causes The Rare Phenomenon Of Volcanic Lightning?

With news channels talking lately about Mayon Volcano erupting in the Philippines, the effects of a volcanic eruption have been repeated. One rare and fascinating phenomenon that happens during some eruptions is volcanic lightning. Pictures of lightning storms within the ash cloud coming from a volcano look surreal. Although this lightning remained a mystery for centuries, scientists have started to unravel it.

What Causes Volcanic Lightning?

According to an article published by LiveScience, scientists looked to ash clouds for answers. Scientists knew that normal lightning in the sky is caused by colliding ice crystals, which create enough electricity to produce lightning bolts. However, ash clouds from volcanoes are harder to study than ice crystals. It does not seem to make sense that ice crystals could collide or even exist in a fiery volcanic ash cloud. While they may not exist closer to the lava, they can exist at a greater distance.

In past studies, scientists suggested that static electricity above a volcano contributed to lightning strikes along the ash cloud. They also hypothesized that strikes reaching above ash clouds were triggered by ice crystals colliding up higher in the stratosphere.

Verifying Volcanic Lightning Hypotheses

A study on volcanic lightning was conducted at Sakurajima in Japan, which is one of the most active volcanoes worldwide. Researchers compared electromagnetic data and infrasound to a video, which revealed that ash clouds produced particles of static electricity. Those particles caused lightning by colliding.

In a separate study, researchers verified that ice had formed above the thickest part of the ash cloud when a Chilean volcano erupted in 2015. The bolts struck near the volcano and were about 12 miles above the ground’s surface. Based on these studies, scientists are confident in their original hypotheses about the causes of volcanic lightning.