中国地质大学：《构造地质学》课程PPT教学课件（英文版）Lecture 27 REGIONAL STRESS REGIMES

REGIONAL STRESS REGIMES AND CHINA TECTONICS

REGIONAL STRESS REGIMES AND CHINA TECTONICS

REGIONAL STRESS REGIMES (ANDERSON THEORY OF FAULTING) lo, is located parallel to the fault plane, normal to the direction of slip/ l o3 is located normal to o, and o2/ Earth's surface is a principal plane ofstress Ideal fault geometry 3 stress regimes: Normal, Thrust, Strike-slip

REGIONAL STRESS REGIMES (ANDERSON THEORY OF FAULTING) • [s2 is located parallel to the fault plane, normal to the direction of slip] [ s3 is located normal to s1 and s2 ] • Earth’s surface is a principal plane of stress • Ideal fault geometry • 3 stress regimes: Normal, Thrust, Strike-slip

Fault orientation in relation to principal stress axes (After EM.Anderson, 1951) A Normal fault sets. B Thrust fault sets. C Strike-slip fault sets

Fault orientation in relation to principal stress axes (After E.M.Anderson, 1951) A Normal fault sets. B Thrust fault sets. C Strike-slip fault sets

1234 B Distribution of potential faults from uniform compressive stresses at two ends(After W Hafner, 1951) 1. Stress 2.Trajectories of maximum principal stress 3. Trajectories of minimum principal stress 4 Potential fault

Distribution of potential faults from uniform compressive stresses at two ends(After W.Hafner,1951) 1.Stress 2.Trajectories of maximum principal stress 3.Trajectories of minimum principal stress 4.Potential fault

1234 Distribution of potential faults result from non-uniform boundary stress(After W Hafner, 1951

Distribution of potential faults result from non-uniform boundary stress (After W.Hafner,1951)

High Friction Low Friction Convergent Margin Mega-thrust

High Friction Low Friction Convergent Margin ‘Mega-thrust’

The Velocities of the Tectonic plates respect to the earth's center FDoF的 P Earth M LNAY0O 2000

The Velocities of the Tectonic Plates with respect to the Earth’s center

CALCULATE RELATIVE MOTION VECTOR FROMABSOLUTE PLATE VELOCITIES RMV Plate 1 V2 Plate 2 Fix Plate I by subtracting VI from itself Then must also subtract vi from v2. The aIt is the re lative motion vector of plate 2 with respect to plate 1

Plate 1 Plate 2 V1 V2 RMV Fix Plate 1 by subtracting V1 from itself. Then must also subtract V1 from V2. The result is the relative motion vector of plate 2 with respect to plate 1. CALCULATE RELATIVE MOTION VECTOR FROM ABSOLUTE PLATE VELOCITIES

Normal Faulting regime σ2&o3 are horizontal, 1 o, is vertical 03 Reverse faulting regime 03 o1 o2 are horizontal, oa is vertical

Normal Faulting Regime Reverse Faulting Regime s1 s1 s3 s3 s2 s2 s2 & s3 are horizontal, s1 is vertical s1 & s2 are horizontal, s3 is vertical

STRIKE-SLIP FAULTING REGIME N p ol view 03 2 o1 o3 are horizontal, o is vertical

STRIKE – SLIP FAULTING REGIME s1 s3 s2 Map view s1 & s3 are horizontal, s2 is vertical