Take Yellowstone for example, we do not know when it will erupt again, but we know sometime in the future that it will. We theorize that its driven from a stationary hotspot system which remains stationary as the Earth's upper crust continually slides over it until a weak spot or a spot of the right construct enables the hotspot to once again erupt. We can observe the size of its previous erruptions to have an idea of what size its eruption could be the next time it goes off. We also know that the eruption will either be violent that gushes upwards into the sky (most predicted), or a gentle spewing out of lava (not expected). When it comes to volcanos erupting the ash cloud reaching into the stratosphere tends to do as much and usually more harm than the actual lava. But the thing about volcanos is, volcanos and volcanic hot spots are dead give aways as to where they shall be occuring, and they tend to heat up and show activity before going off. I would think that it would be possible to place some sort of domed barrier over a volcano before it errupts to limit its harm to the planet. Even if lava punches holes through it, I would still imagine that a good percent of its environmental damage could be somewhat maintianed. I would also assume that full dome coverage wouldn't be required to limmit the damage, but rather a partial dome structure would perform almost as well. Not sure the materials that would work or be needed, or how transportable it would be, but I could forsee the use of such an protection program... volcano becomes active, helecopter over and place down a splatter shielding system. Thoughts on this... is it a good idea or not, could something like this work, and how could it be achieveable?