GEOL 104 Lecture Notes - Lecture 22: Megathrust Earthquake, Epicenter, Subduction
Document Summary
Faults and joints: rock structures formed by brittle deformation: faults. Fractures in rocks, along which displacement occurred. Give evidence for direction of movement along the fault: dip-slip faults. Occur when movement is parallel to inclination: hanging wall is rock surface above fault, footwall is the rock surface below. The vertical displacement along the fault produces long, low cliffs called fault scarps. Characterized by hanging wall moving down relative to footwall: associated with tensional stress as the rocks pull apart. Larger scale normal faults are associated with fault-block. Detachment faults represent the boundary between ductile and brittle rock units. Characterized by hanging wall moving up relative to the footwall: associated with compressional stress as the crust shortens. Klippe is the erosional leftovers of a thrust fault and weathering. Characterized by placement that is horizontal and parallel to the strike of the fault. Types of strike faults: strike-slip faults mountains. Thrust faults transform faults: left lateral (sinister, right-lateral (dextral)