Volcano Eruptions: Causing Tsunamis - through 2010

According to the Smithsonian Institute's Global Volcanism Program, there are probably about 20 volcanoes erupting right now, and about 550 volcanoes have had historically documented eruptions. A volcano is an opening, or rupture, in the Earth's crust through which molten lava, ash, and gases are ejected. Volcanoes typically form in three different settings. The first is divergent plate boundaries, where tectonic plates are pulling apart from one another, such as the Mid-Atlantic Ocean Ridge. Most of these volcanoes are on the bottom of the ocean floor and are responsible for creating new sea floor. The second location is convergent plate boundaries, where two plates, typically an oceanic and continental plate, are colliding. The volcanoes along the Pacific Ring of Fire are from convergent plate boundaries. The third location is over hotspots, which are typically in the middle of tectonic plates and caused by hot magma rising to the surface. The volcanoes on Hawaii are the result of hotspots.

There are three datasets for Science On a Sphere that highlight global volcano locations. This dataset is from the National Geophysical Data Center's Significant Volcanic Eruption Database and shows the locations of all eruptions that have caused tsunamis. Also available from NGDC is a dataset that shows the locations of all significant volcano eruptions, of which there are over 400. An eruption is considered significant if there are any fatalities linked to it, the cost of the damage is over one million dollar, it causes a tsunami or there is a major earthquake associated with it. The last dataset, Volcano Locations Globally from Smithsonian Institute's Global Volcanism Program shows the locations of current and past activity for all volcanoes on the planet active during the last 10,000 years.