• volcanoes
• Hawaii Volcano Observatory
• Mt. Fuji
• Mt. St. Helens
• Mt. Saint Helens: Subduction zone volcanism
• A Geological guidebook to "Volcano Movies"
• Volcano! (The Movie)
• Dante's Peak (The Movie)
• Yellowstone National Park
• Classification of igneous rocks
• A brief description of a hotspot
• A more complete description of a hotspot
• The Big Island of Hawaii: An oceanic hotspot
• Yellowstone: A continental hotspot
• Another trip to Mt. Saint Helens: Subduction zone volcanism
• Stromboli on-line
• Live images of Mt. Etna

• A (well-done) Snell's Law program
• The derivation of the Adams-Williamson equation
• refraction.html
• The USGS Ocean Bottom Seismometer Facility
• Seismic refraction experiments carried out by US scientists
• Seismic tomography across a subduction zone
• Is the inner core rotating at a different speed than the mantle?
• Seismic probing beneath the Himalayas: Continent-continent convergence
• The 1811-1812 New Madrid, Missouri earthquakes in the middle of the North American plate
• An interactive example of earthquake location and magnitude determination
• The San Andreas Fault: A transform fault between the Pacific and North American plates
• The 1989 Loma Prieta earthquake on the San Andreas Fault
• Locating earthquakes
• Introduction to earthquakes and seismic waves
• A tutorial on seismic reflection
• Getting seismological data from the Internet
• Ocean Bottom Seismometers: How they work
• What is an Ocean Bottom Seismometer?
• Understanding earthquakes: an introduction with nice animations
• The National Earthquake Information Center
• Getting seismological data from the Internet
• Other sources of earthquake information on the internet
• Tsunami information
• Understanding earthquakes

Miscellaneous

• How plate tectonics gives rise to earthquakes
• Earthquakes and Plate Tectonics
• Geologic hazards
• The USGS Landslide Information Center
• Coasts in Crisis
• Highlights of the USGS Coastal and Marine Geology Program