Faults
Fault A fracture, or break, in Earth’s lithosphere, where movement occurs.
Stress A force that presses on, pulls on, or pushes against another object.
Earthquake The ground shaking caused by the sudden movement of large blocks of rock around a fault.
Rocks move along faults Most faults are located along tectonic plate boundaries. Very little movement actually happens during an earthquake. Earthquake belt: 80% of earthquakes happen here Around the Pacific Ocean San Andreas fault North American Plate & Pacific Plate come together In California Earthquakes occur in the lithosphere
San Andreas Fault
How Faults are Classified 3 types of faults Normal fault Reverse fault Strike-slip fault Faults are named based off of how rock moves
Normal Faults Stress that pulls rocks apart is what causes this fault. Tension forces Pulling Apart Footwall moves upward Part you can stand on Hanging wall moves downward Part you hang from
Reverse Faults Caused by rock being pushed together Compression forces Pushing Together Footwall moves downward Hanging wall moves upward
Strike-Slip Fault Rocks move side by side Caused by shearing forces
Whose Fault?
Normal Fault – Foot Wall Up
Whose Fault?
Reverse Fault – Foot Wall Down
Whose Fault? Birds-eye View
Strike Slip – Side By Side Birds-eye View
Whose Fault? Side View
Normal Fault – Foot Wall Up
Whose Fault? Side View
Reverse Fault – Footwall Down Side View
Whose Fault? Birds-eye View
Strike Slip – Side By Side Motion Birds-eye View