So, apparently a few people worry about the after effects of a super eruption such as from Yellowstone. As I previously posted
here there are considerable hazards from volcanoes, but a super eruption
poses more problems than these, and also these problems over much larger areas.
This is a picture showing the ashfall that has occurred from some of the Super eruptions, those of Yellowstone and Long Valley:
As can be seen, the dangers of ashfall extend a long way from the volcano itself. The total extent may be even larger, as small deposits can easily
be buried later and hidden. A very small amount of ash either in the air or around airports are severe dangers to aviation, for example
British Airways Flight 9 was very lucky not to crash due to damage to it's engines
by volcanic ash.
Obviously, due to the large volume of ash, the amount of ashfall would be very heavy on the nearby areas, considerably larger than anything ever seen
before.
The sulphur emitted also creates acid rain, and cools down the planet in a volcanic winter, similar to a nuclear winter, different only in cause.
As a result of volcanic winter, food can become scarce, and this can create more familiar survival problems, but in areas affected by the ash it will
be an even larger problem than usual, as only stored food will be truly safe, as ash can get everywhere due to its small size.
Obviously I put 'after' in the subject title, as during it shelter is best, unless your really close, where the only option is to
run, or
similar to get away really quickly.