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)

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

1. Calculate the force at the base of a continental block that has a uniform thickness of 25km, length of1000km, width of500km, and density of2.70. What is the stress on the bottom of the block?

一、名词解释（20 分，每小题 2 分） 1. 递进变形：从初始状态至最终状态之间，岩石变形的全过程，用于理解和描述变形 过程（演化）。）

1. What is the significance of the concept of \principal stress\? 2. Sketch a 2D stress ellipse for the case 01=5GPa and 02= 2GPa where 01 is vertical

1. Place all books and notes on the foor 2. Read each question carefully, then read it again 3. Think before you write