There is a chicken and egg relationship between faults and earthquakes 1) It was initially thought that earthquakes caused faulting(but then what caused the earthquake?) 2) It was later realized that faulting produced the rthquak Thus earthquakes may occur because a rocks are initially broken to produce a fault b) Movement or re-activation of an already existing fault [Faults may therefore be thought of as fossil relicts of previous earthquakes Folding and Faulting TENSION COMPRESSION COMPRESSION - causes rocks to fold and ultimately break to produce a fault TENSION causes rocks to stretch and also break to produce a fault Faulting also occurs in response to shearing stresses3 There is a chicken and egg relationship between faults and earthquakes 1) It was initially thought that earthquakes caused faulting (but then what caused the earthquake?) 2) It was later realized that faulting produced the earthquakes. Thus earthquakes may occur because:- a) Rocks are initially broken to produce a fault. b) Movement or re-activation of an already existing fault. [Faults may therefore be thought of as “fossil” relicts of previous earthquakes] Folding and Faulting COMPRESSION – causes rocks to fold and ultimately break to produce a fault. TENSION – causes rocks to stretch and also break to produce a fault. TENSION COMPRESSION Faulting also occurs in response to shearing stresses