Super Volcano Hazards
1) Initial explosive shockwave, magma flow and ejecta.
2) pyroclastic flow
3)
Volcanic AshVolcanic ash is the result of the violent explosion of rock, forming minute shards of glass with jagged edges, which is obviously not soluble in water. Just a few inches of this can collapse a roof. Add water to this and it will certainly collapse a roof and many structures. The evident voids and fissures seen in the image below quite a job holding water, making saturated ash accumulation extremely heavy.
Moist ash, resting on power lines, would short insulators, and cut off power to large portions of the country.
If volcanic ash gets in one's lungs, a person can easily suffocate from that ash, which again will not dissolve in body fluids.
However if one only inhales some ash, but does not die from immediate suffocation, that jagged ash particulate will lacerate the lungs, causing tremendous pain, and something even worse - similar to Marie's disease.
The fine ash in the lungs triggers a biologic mechanism that results in the rapid growth of new bone all over the body. THis new bone growth causes arthritis-type pain all over the animal's body. They die after having endured a long period of absolute agony - hideous about covers it.
Imagine that your body is slowly dying from your lungs being incapable of taking in sufficient oxygen.
So bone is dying, from directing oxygen to the vital organs instead, and the body's defense is to
generate new bone. And that is causing you even more agony.
A paleontologist, Mike Vorhees, discovered this effect from volcanic ash inhalation and "Marie's disease" in the 70's,
found from fossilized skeletons at a watering hole, described in this video at the
time marker 26:50 to 31:41.
Video:
Naked Science: Super VolcanoFurthermore, the ash can settle over the breadbasket of the country, first killing all cattle and livestock, and then settling down on the land to depths of feet, traveling even 1000's of miles to do so. This ash will remain there generally, and is incapable of growing plants, because it is biologically inert.
Then there's the longer term "dimmer effect" to the atmosphere, causing the equivalent of a nuclear winter, diminishing the growing season to an interval where plants cannot be harvested before being killed by frost in many farming regions. And this will happen all over the planet for years to come.