90% of all volcanic activity occurs in the ocean.

due to the tambora volcano, there was no summer in 1816. snow fell, even in summer, from maine to virginia.

when the krakatoa volcano exploded with a force that was 4 times greater than any nuclear weapon ever tested. the noise was so loud that it could be heard 2,000 miles away, a distance so great that it took 3 hours for the sound to ravel that far. the explosion killed 40,000 people, turned 1 island into 3, changed the weather for the next 5 years, and dropped the entire planet's temperature by 2 degrees.

3 tectonic plates meet at the izu islands, off the coast of japan. as a result, there are volcanoes, one of which has been spewing so much sulphur dioxide for the past few years that residents have to wear gas masks every hour of the day to avoid death.

herculaneum, which was closer to mt. vesuvius than pompeii, only got a light dusting of ash - at first. then, at about 1 am on august 24th, 79 a.d., anyone who hadn't evacuated was burned alive by a 1,000 degree fahrenheit pyrochlastic flow of gas and molten rock moving at more than 100 miles an hour that literally boiled their brains, exploded their heads, evaporated everything but their bones, and buried their city under 25 meters of ash.

if you died in lava, you wouldn't sink; lava is too dense for that (it's liquified rock, after all). instead, you would burst into flames on its surface.

in 1986, a crater lake in cameroon emitted a large quantity of carbon dioxide. it suffocated 1700 people and their livestock, and turned the lake water into carbonic acid.

when the krakatoa volcano erupted, it created a pressure wave that circled the globe 7 times.