GEOL 003 Lecture 5: Chp. 5 - Earthquakes
Document Summary
Fault - a fracture in the crust on which movement has occured. A zone of weakness where earthquakes occur. Focus - location where movement begins on fault. Epicenter - location on surface above the focus. Fault scarp - step in land surface formed by movement on the fault. Only part of a fault typically breaks during an earthquake. Normal fault, block above an inclined fault moves down. Reverse fault, block above an inclined fault moves up. Strike-slip fault, blocks on either side of fault move horizontally, left or right. Fault movements are driven by stresses produced by plate tectonics. Friction along the fault surface is enough to cause most faults to. Stress continues to build: rocks closer to fault bend like an archer"s bow. The buildup of stress causes the rock to deform or change shape. After decades or centuries, stress has built up to sufficient levels to overcome friction and cause fault movement.
