Tsunami Statistics-http://tsunami.name

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

Markus Valovski-http://earthquakedb.com

Professional earthquake database with information about the currently known earthquakes in history, with RSS feeds and an earthquake search engine.

Types of Volcanoes-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.