1. Distribution of Deformation in the Crust divide the crust into deformation regimes based on temperature and depth A. Upper Crust (0 - 50 km)

Tectonic Earthquakes Most earthquakes occur at plate margins due to tension, compression or shearing forces. Rocks at plate margins are in constant motion and are being pushed, pulled, bent, twisted and folded

There will be a brief review of chapters 7 ñ 11 at the end of this lecture. There will be no lecture on Tuesday, November 13, 2001 (Reading Days)

Department of Earth and Space Sciences, University of California, Los Angeles The unifying theme in this section is the remarkable weakness of major faults. I will consider the diverse new evidence for weakness, and the evidence for high pore pressure localized in faults as a fundamental cause. With this background one can better understand why faults remain active even after large rotations with

Recognition of fault bend fold, detachment and decapitation has been possible despite the poor quality of the seismic. That was successful because of: A full integration of all disciplines including reservoir engineering petrophysics and geochemistry Vizualization in 3-D that made all members of the team speak the same language

Brittle deformation = the permanent change that occurs in a solid material due to the growth of fractures and/or sliding on fractures. A fracture is a surface of discontinuity (includes cracks, joints and faults). Faults result from shear stresses, and joints result from tensile stresses:

what you always wanted to know about folds, faults, and joints Stress = the force applied to a plane divided by the area of the plane

The change in volume or shape of an object that results from stress is called strain. The response of rocks to stress can be divided into - elastic response: rock returns to original shape - ductile or plastic response: permanent deformation without fracture; occurs above the so-called elastic limit

STRIKE - The direction of the line formed by the intersection of a horizontal plane with a bedding or fault plane. DIP - The angle formed by the intersection of a bedding or fault plane and the horizontal plane. The angle is measured in a vertical plane perpendicular to the strike

We will now approach the function A(a) from an entirely different point of view, i.e.,we will interpret the S-fabric in terms of strain1. (1.) We assume that the initial fabric is defined by a random orientation of surface, i.e.,that the ODF of the surface is uniform;