I never realize Volcano is such a big threat to mankind that it could doom all of us. My impression of Volcano are those cone shape mountains with lava flowing in Hawaii or Japan. Actually those kind of Volcano are quite harmless, only affect area on the way of the lava rivers. Mount St. Helen near Portland is a different kind of Volcano. It does not have an open top, so pressure builds up inside the mountain. When it erupted in 1980, the shock wave and ashes kills everything within a few kilometers. Towns as far as 30km are covered with ashes. I remember there was a movie called Volcano in which the fire fighters heroicly blocking the flow of lava and save the city. Actually in an eruption, the lava is the last thing you should worry about. It moves so slow that it is only a logistic question to let everybody escape. The most deadly things from an eruption are the ashes. Near ground zero, the high pressure ashes will cut through anything on its way. When the shockwave dies down, the ashes in the air is so thick that it is unbreathable. For a large area, although there is no immediate danger, the ashes covers the land. The ashed land is not suitable to grow crops for many months or even years.? There are so many ashes from St. Helen that it can bury Manhatten under 20 meters of Ashes. The damage caused by St. Helen is very bad but not fatal to mankind. The whole Yellow Stone national park used to be a super volcano millions of years ago. When it last erupted, the ashes makes lands within 1000km radius unlivable and affect people on the other side of the globe. It has enough ashes to cover California 6m deep. If a super volcano erupt today, at least half of the world’s population would die. Unfortunately, with our current understanding of Earth and technology, we can’t do much about the super volcano except pray for it wouldn’t happen.