Earthquakes:
http://www.pbslearningmedia.org/resource/nvsn5.sci.earth.gps/using-gps-to-study-earthquakes/
Volcanoes:
https://docs.google.com/a/rossrams.com/spreadsheet/viewform?formkey=dDg5MW9rcDFQYWxISTR1UzhyNmRMM0E6MQ
www.quizlet.com/8811684/volcano-fill-in-flash-cards/