Quote:
Originally Posted by glatt
Awesome image. I love how the lightning is finding its quickest path to the ground through the hot ash.
|
Especially in the second Volcán Chaitén pic, glatt, the lightning looks 3-D and finely branching throughout the ash cloud.
I've found some nice pics of other volcanoes, but not with such a striking (whoops
) combination of lightning and dense ash.
Sakurajima, Japan
"Explosive eruption with lightning at Sakurajima Volcano . . . 18 May 1991"
Larger version
Mt. [St.] Augustine, Alaska
"Scientists: Lightning good indicator of volcano eruptions
". . . For the first time, scientists were able to collect data fully describing lightning activity during the 2006 Mount Augustine eruption, according to an article published last week in the journal
Science. . . .
"During the initial Augustine eruptions in 2006, airline pilots reported lightning in the ash plume. This prompted McNutt to install new lightning detection instruments . . . capable of detecting the exact location and source of each lightning bolt. . . .
"Volcanic ash clouds are similar to thunder clouds, explaining why lightning is often seen during large eruptions. In volcanic ash clouds, an electric charge is generated from the friction of ash particles expelled into the air, particle collisions and rock fractures.
"Ash clouds from large eruptions are composed of particles of various sizes. Larger particles tend to be negatively charged and fall to the base of the cloud while smaller positively charged particles remain near the top, re-creating the same electric distribution seen in thunderclouds. As charges and particles build up[,] energy is released in the form of lightning."
Full article from University of Alaska Fairbanks newletter.
"Lightning strike over [unidentified] volcano"
"Electrical Activity During the 2006 Mount St. Augustine Volcanic Eruptions
"By using a combination of radio frequency time-of-arrival and interferometer measurements, we observed a sequence of lightning and electrical activity during one of Mount St. Augustine's eruptions. The observations indicate that the electrical activity had two modes or phases. First, there was an explosive phase in which the ejecta from the explosion appeared to be highly charged upon exiting the volcano, resulting in numerous apparently disorganized discharges and some simple lightning. The net charge exiting the volcano appears to have been positive. The second phase, which followed the most energetic explosion, produced conventional-type discharges that occurred within plume. Although the plume cloud was undoubtedly charged as a result of the explosion itself, the fact that the lightning onset was delayed and continued after and well downwind of the eruption indicates that in situ charging of some kind was occurring, presumably similar in some respects to that which occurs in normal thunderstorms."
Abstract from Science mag; page has links to full text (registration required to view).
Galunggung, Java, Indonesia
"Lightning above the summit and glowing pyroclasts on the flank of Galunggung . . . September 16, 1982."
"Confocal images of rat optic nerve glia, intracellular dye-filled with lysinated rhodamine dextra (a, b), or immunofluorescence labelled with the NG2 anibody (c, d)." :p