Geography

Browse all the currently known volcanoes with map locations, times of eruptions and much more!
http://volcanodb.com

This is a free online volcano database, with information about all the currently known volcanoes. Every volcano features the basic statistics, as well as a very detailed map, with bot urban and satellite photos, and a google earth placeholder.
http://volcanodb.com/

Professional tsunami database with information about the currently known tsunamis in history, with RSS feeds and a tsunami search engine
http://tsunami.name

Professional earthquake database with information about the currently known earthquakes in history, with RSS feeds and an earthquake
http://earthquakedb.com