Volcanoes are awesome manifestations of the fiery power contained deep within the Earth. These formations are essentially vents on the Earth’s surface where molten rock, debris, and gases from the planet’s interior are emitted. When thick magma and large amounts of gas build up under the surface, eruptions can be explosive, expelling lava, rocks and ash into the air. Less gas and more viscous magma usually mean a less dramatic eruption, often causing streams of lava to ooze from the vent.
The mountain-like mounds that we associate with volcanoes are what remain after the material spewed during eruptions has collected and hardened around the vent. This can happen over a period of weeks or many millions of years.
The secret of what causes volcanic lightning a strange and violent form of lightning that only happens inside the ash clouds of erupting volcanoes, has finally been cracked. Not only have researchers in Germany figured out where volcanic lightning comes from, they might have also found a new way to measure how much ash a volcano is spewing out in real time, which will help us to predict air quality during and after eruptions.
Before we dive headfirst into volcanic lightning, we need to understand some basics about normal lightning. Lightning forms inside a cloud when a mix of warm and cold air causes a static electrical charge to build, with the top of the cloud having a positive charge and the bottom having a negative one. “In the early stages of development, air acts as an insulator between the positive and negative charges in the cloud and between
the cloud and the ground,” explains the National Severe Storms Laboratory (NSSL).
“When the opposite charges builds up enough, this insulating capacity of the air breaks down and there is a rapid discharge of electricity that we know as lightning. The flash of lightning temporarily equalises the charged regions in the atmosphere until the opposite charges build up again.”
A similar thing happens in volcanic lightning, with an electrical charge building up, but there are some big differences, too. Volcanic lightning, for example, forms closer to the ground, and doesn’t always move downward in the same way that normal lightning does.
Until tomorrow: If you young fellows were wise, the devil couldn’t do anything to you, but since you aren’t wise, you need us who are old.
Dorothy Prats / [email protected]