athel

Well, a few calculations on this...Type II supernova at 640 light years giving 10^46 Joules during a 10 second core collapse is 10^45 Watts. This is radiation at all wavelengths similar to that from a nuclear bomb. A negligible one per cent creates the neutrino driven Baryon expansion, the rest of the energy flashes out into free space and the intensity on a sphere at a given radius can be calculated.

The intensity at the Earth is 2.5*10^6 Watts per sq.m. for 10 seconds. Maybe as much as one half will be thermal radiation. An online figure quoted for the ignition of e.g. dry vegetation for the initiation of fires after a nuclear weapon explosion was 125 Joules per sq.cm. It looks like we may get ten times the dose needed to start fires across much of the land mass. Needless to say we would not want to be observing this event so the best place to avoid the thermal radiation is at the USA base on the south pole. I always wondered why they had so many people down there! They could well be wasting their time though. I have no information on the effects of the massive doses of gamma radiation which will pass through the Earth shield and there may be significant refraction of the thermal radiation over the polar horizon. Well, this is my brief analysis and I am not an expert on supernovae. I just wonder how much warning we may get?