Question: Do errupting volcanos relate to other natural disasters such as the earthquake in Japan

David Pyle answered on 18 Mar 2011:

Good question! It does appear that very large earthquakes can disturb dormant volcanoes, and trigger small eruptions. There seem to be some examples of this from last week’s Japan quake already – with stories of small eruptions at two Japanese volcanoes, and possible eruptions further away in Russia and Indonesia. Charles Darwin was the first to notice this link, following a large Chilean earthquake in 1835.

On a more general scale, most volcanoes and earthquakes are usually associated with the boundaries between tectonic plates – so they do tend to occur in the same sorts of regions. There are some important sorts of boundaries (e.g. those with strike-slip faults which move sideways) where you only get earthquakes, and not volcanoes – like the San Andreas Fault.