Two thousand years ago, the Greek historian and philosopher Pliny the Younger recorded the appearance of lightning during the eruption of Vesuvius. But only in 2000, American volcanologist Steve McNatt established the nature of this strange and very colorful phenomenon.
McNatt was able to establish the causes of lightning - seismological and electrical.
It turned out that lightning over volcanoes can be divided into two types. The first ones appear right at the crater and are not very large. The latter are formed high in the ash clouds and now they look very impressive. Low lightning is created by electrical processes in magma, and high lightning appears in ash clouds due to temperature differences.
In addition, it was statistically established that lightning occurs more often in very high (over 7 kilometers) volcanic clouds. How often they hit depends on the amount of water in the magma: as long as the pressure in the magma is high, it prevents the water from boiling away.
Promotional video:
But when magma bursts out of a volcano, the water instantly turns into steam, which helps to form a thunderstorm front.