The Shinmoe-Dake Volcano in Japan erupted just two days after the earthquake.  Check out the links below:

http://hken.ibtimes.com/articles/122076/20110314/japan-shinmoedake-volcano-shinmoe-dake-erupted-erupts-ash-rock-earthquake-tsunami.htm

http://nation.foxnews.com/culture/2011/03/14/japans-shinmoe-dake-volcano-erupts