One of the most spectacular images of volcanic lightning was the recent Chaiten eruption above showing some of the most intense plasma displays I have ever seen. The conventional explanation for this lightning is similar to that presumed for thunderstorms, which is not completely understood. The theory is that charge separation is caused by volcanic dust particles colliding and building up static charges, but as David Adam of The Guardian Newspaper writes "The violent electrical storms that break as a volcano erupts mystify scientists. David Adam reports on a new explanation for the explosive phenomena – and the surprising amount of water in magma".
"There are now more than 150 recorded cases of vicious electrical storms breaking out directly above craters of erupting volcanoes, dating back several centuries. The 1980 eruption of Mount St Helens in Washington state, one of the most studied eruptions in recent times, produced a lightning bolt every second. The electrical activity does not pose the same hazard as a volcano’s boiling lava, choking dust clouds and drowning mud slides – though there are reports of people and animals being struck as they fled – but it sets a spectacular seal on mother nature’s most awesome display of destruction".
Now some scientists think that volcanic lightning is really a dirty thunderstorm. Really?
Credit: Sakurajima Volcananological Observatory
Caption: Sakurajima volcanic lightning, May 18, 1991.
And there are other problems to the standard theory because new discoveries have deepened the mysteries of volcanic lightning. A recent news story reports on a study into volcanic electrical phenomena occurring in the eruption of Mt. Augustine in Alaska. The web site LiveScience.com writes: "The lightning in a volcanic eruption occurs because the ash and other debris blasting out of the volcano are highly charged…. Though lightning was known to occur in the debris clouds above the volcano, the researchers found an earlier phase of volcanic lightning that had never before been observed and occurred right at the volcano’s mouth just as it began erupting."
In other words, the lightning preceded the supposed “charge separation” process from friction that has traditionally been claimed to occur in billowing volcanic clouds. One of the researchers described this phase of the volcanic lightning as "big sparks maybe going just from the mouth of the volcano up into the column that’s shooting out of the volcano, and then some lightning that went upward from the top of the volcano up into the cloud that was forming."
The report is ambiguous in speaking of “highly charged” debris rather than of moving ash and dust “separating charge.” “Charged debris” is much closer to the language that would be used by the electrical theorists. They consider the volcanic electrical activity to be a consequence of a pre-existing electric field that is short-circuited by a conductive medium. The earth’s electric field under quiescent conditions is 100 volts per vertical metre.
But why do some volcanoes produce lightning while others don’t? More curious, why do some volcanoes with large dusty plumes produce little or no lightning and others with small or mediocre plumes produce much lightning? The simple answer could be that all volcanoes are electric but that the lightning displays happen only when the resistance to the volcanic current is high. You have a good example of this in your home. The electric wires that carry the current from the wall socket to your lamp don’t produce heat or light. But when that same current encounters the high resistance of a tungsten filament, it does produce heat and light.
From an electric universe point of view, the Earth is a small charged body moving in a large cell of plasma. Because of this, explanations of all physical phenomena in, on, and near the Earth must take the electrical behaviour of plasma into account. The Physics of the Plasma Universe by Anthony Peratt describes magma as a plasma, a medium containing moving charges. So we should expect volcanoes not only to exhibit electrical behaviour but to have that behaviour connected with the larger plasma environment, that is, to be elements in a larger electrical circuit.
By studying the electrical component of volcanoes on Earth, plasma geologists can gather clues about the mysteries of Earth’s volcanic geologic history. For example, it may help to explain why volcanism in the past — the great basalt floods — was hotter and more voluminous than in the present.