What causes earthquakes in the Basin & Range province?
Cross section of the shallow crust in the Basin & Range. Earthquake produces seismic waves that bump an array of seismic stations. One station records the arrival of the seismic waves on a seismogram. Earthquakes are shallow in the Basin and Range (15 km deep or less). A shallow earthquake is more likely to create a break in the surface of the earth than a deeper one, particularly if it's large. The movement during Basin and Range earthquakes is a stretching apart motion, causing one of the fault to drop down past the other and create a scarp.
During Basin & Range extension:
- The crust stretches and stress builds
- Friction is overcome and a block drops
- Sudden movement releases seismic energy in the form of an earthquake
- Seismic waves travel away from the earthquake in all directions.