Subject
Earth sciences
4
Earthquakes
Geology
4
Continental crust
3
Continental drift
3
Earth (Planet)
3
Earth (Planet) Core
3
Earth (Planet) Crust
3
Earth (Planet) Surface
3
Erosion
3
Glaciers
3
Groundwater
3
Minerals
3
Mountains
3
Ocean
3
Plate tectonics
3
Rocks
3
Volcanoes
3
Faults (Geology)
2
Floods
1
Fossil fuels
1
Geological time
1
Geophysics
1
Igneous rocks
1
Loma Prieta Earthquake, Calif., 1989
1
Metamorphic rocks
1
Petroleum as fuel
1
Petrology
1
Renewable energy sources
1
Richter scale
1
Rivers
1
Sedimentary rocks
1
Seismology
1