Washington: Three-dimensional imaging has shown that the eruption of Alaska’s Redoubt Volcano last year, created a new type of lightning, in the form of small, quick sparks.
“We long suspected that the first eruption might be different - and it was,” University of Alaska volcano seismologist Stephen McNutt said.
By monitoring seismic data, researchers were able to get a jump on Redoubt and set up lightning detectors in the area two months before the volcano blew.
Three-dimensional pictures produced from the arrays showed - for the first time - tiny sparks of lighting lasting just a millisecond or two inside the volcano`s ash plume at the start of the eruption.
The team also mapped two other types of previously documented, though poorly understood, volcanic lighting: large bolts, stretching for several miles, which are similar to what is produced during thunderstorms; and intermediate-sized bolts up to about two miles in length that blast out of volcanic vents.
Scientists don’t know why some volcanoes spark huge lightning displays, while others have none.
However, they did notice a relationship between the amount of lightning from a volcano and the size of its plume.
Redoubt had a series of more than 20 eruptions over 13 days last March, all of which were accompanied by lighting flashes.
“In general, the higher the plume went, the more lightning we got,” said Ronald Thomas, a physicist and electrical engineer at the New Mexico Institute of Mining and Technology.
The physics of what’s happening are still to be determined, but scientists are hopeful the research will lead to new ways to monitor and assess volcanic eruptions.
The research team hopes to follow up the Redoubt Volcano studies by mapping lighting at other erupting volcanoes.