Slide 2 of 24
- What is an earthquake?
- Earthquakes are perceptible movements of the earth’s surface.
- Primary cause of earthquakes is the rupture of faults in the earth’s crust and the associated rapid slip on these faults.
- Large and damaging earthquakes are caused by rupture of faults that are tens to hundreds of miles long.
- Sometimes the fault rupture reaches the surface and we can see the movement on a fault.
- Strong earthquakes often occur, however, even when the fault rupture does not reach the surface (egs. 1989 Loma Prieta, 1994 Northridge).