Ah, there's a picture like that on the cover of my textbook. Lots more
red, it was a firey eruption photographed at night. Book is:
Halliday, Resnick, Walker, _Fundamentals of Physics_, 6th ed., John Wiley &
Sons, Inc. (2001)
Says cover photo: Tsuyoshi Nishiinoue / Orion Press
This photo is used as the basis of Chapter 23, which starts with:
"During the frequent eruptions of the Sakurajima volcano in Japan, multiple
electrical discharges (sparks) flash over the volcano's crater, lighting up
the sky and sending out sound waves that resemble thuunder. However, this
is not a lightning display in a thunderstorm, with electrified clouds of
water drops discharging to the ground. This is something different."
So here's the mountain,
http://en.wikipedia.org/wiki/Sakurajima
And I won't quote the entire explanation, but the important part given is:
"...Ash results when liquid water within the volcano, suddenly converted to
steam by the flow of hot lava, shatters rock, which is then burnt. The
liquid-to-steam conversion and the explosion of rock cause positive and
negative charges to seperate. Then, as the steam and ash are spewed into
the air, they form a cloud that contains pockets of positive charge and
pockets of negative charge."
So there ya go, D f BC ;-)
Tim
..)