Tectonic plates
http://pubs.usgs.gov/gip/dynamic/understanding.html
www.pbs.org/wgbh/aso/tryit/tectonics/
Earthquakes
www.weatherwizkids.com/earthquake1.htm
Richter Scale
www.fema.gov/kids/intense.htm#earthquakes
www.teacher.scholastic.com/activities/wwatch/earthquakes/
http://pbskids.org/zoom/activities/sci/seismometer.html
Volcanos
www.nationalgeographic.com/ngkids/0312