The Big Pine, Garlock, And San Andreas Fault

929 Words May 11th, 2016 4 Pages
The three faults being considered are thought to have influenced the character of some 120,000 square miles. The Big Pine, Garlock, and San Andreas faults are all mutually active, deep, long, and steep and noted as being conjugate shears. In concert, the faults have defined a primary strain pattern of relative east-west extension and north-south shortening of the area of 120,000 square miles. The large region is noted for its deformity, with the source of this being a northeast-southwest counterclockwise compressive couple. The compressive couple was potentially supported through drag as a result of the deep-seated movement of rock material from the Pacific region (Hill & Dibblee, 1953). The interaction of the faults in the San Andreas region since the Jurassic period have served to shape and contour the present geology of the land, while a study of the paleontology of the region likewise requires such knowledge to effectively determine conditions at any given point in time.
Tectonic Stress and the San Andreas Fault According to Townend and Zoback (2004) the San Andreas Fault (SAF) region has been noted for its possession of stress orientations in addition to the lack of a distinct heat flow anomaly at the trace of the fault. These findings indicate that there are average shear tractions that are less than 20-25 MPa in the seismogenic upper crust. Oftentimes, shear tractions measure approximately 5 times greater than in the SAF. Due to the presence of high…
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