Mechanics of Earthquakes and Faulting

Course web site:

http://www3.geosc.psu.edu/Courses/Geosc508/

Book:

It is strongly recommended that you buy: The Mechanics of Earthquakes and Faulting, C. H. Scholz, 3^rd ed. 2019.

Lecture notes:

Lecture materials will be available on the course web site.

Problem sets:

Problem sets will be assigned via the course web site.

Presentations:

Class meeting will be interactive. I expect you to bring questions and comments on the reading. Please come to the class prepared for that.  Later in the term, we will have student project presentations: come prepared with presentation slides, overheads, or detailed notes to use for the blackboard.

Exams:

Take-home mid-term and final.

Project:

The project will involve data gathering via laboratory experiments or a related area and can be on any aspect of the course.

Grades:

The course grade will be determined from: problem sets (30%), class participation (10%), project and project presentation (30%), and the exams (30%).

Week

Topic

Reading

(Chap. in Scholz)

1.

Brittle Fracture I.  Milestones in continuum mechanics, concepts of modulus and stiffness. Stress-strain relations, elasticity, surface and body forces, tensors, Mohr circles.  Theoretical strength of materials, Defects, Stress concentrations, Griffith failure criteria, fracture mechanics.  Fracture toughness, Surface energy and Fracture energy. Cohesive zone, strain energy and the work of faulting. Macroscopic failure laws.  Coulomb-Mohr criteria and stress-states.

Ch. 1

2.

Brittle Fracture II. The strength of rocks.  Experimental data.  Pore fluid effects. Effective stress laws.  Dilatancy hardening.  The role of stiffness.  Strain rate dependence of rock strength. Brittle vs. Ductile deformation, Dilatancy, Schizosphere, Plastosphere,

Ch. 1

3.

Rock Friction I.  Amonton’s laws.  Concepts of static and kinetic friction. Bowden and Tabor’s theory of friction. Asperities, adhesion, abrasion, wear.  Stick-slip and stability of frictional sliding.  Time dependent and memory effects. Fault re-strengthening and healing.

Ch. 2

4.

Rock Friction II.  Slip rate dependence of kinetic friction. Critical slip distance of friction, Rabinowicz’s experiments. Rate and state friction constitutive laws.  Elastic coupling and solution of history-dependent equations.  Forward models of velocity-step tests and frictional healing.

Ch. 2

5.

Rock Friction III.  Processes and mechanisms of friction, complex behavior, strain rate dependence, slip history effects, normal stress effects.  Forward models and constitutive laws for friction

Ch. 2

6.

Fault Mechanics. Andersonian Faulting.  Hubbert-Rubey theory. State of stress in the crust.  Shear heating. Fault growth.

Ch. 3

7.

Fault Rocks and Fault Strength. Faulting in nature.  Fault rocks and fault zone thickness.  Wear in natural fault zones. Fault zone rheology.  Depth variation of fault rocks and structures.  Fault zone fabrics.  Fault zone heterogeneity.

Ch. 3

8.

Earthquake Mechanics.  Magnitude, seismic moment, quantification of earthquakes. Focal mechanisms, Source parameters.  Particle velocity, rupture velocity.  Seismic stress drop: static and dynamic. Seismic efficiency. Seismic spectra and interpretation.  Rise time, rupture duration.

Ch. 4

9.

Earthquake rupture nucleation.  Friction and fracture mechanics approach to nucleation.  The critical slip distance for seismic faulting.  Critical rupture patch size.  The transition from quasistatic to dynamic rupture.  Laboratory data.  Seismic data.

Ch. 4

10.

The seismic cycle.  Repeating earthquakes.  Rupture characteristics, time dependence.  Relation to laboratory-derived constitutive laws.

Ch. 5

11.

Earthquake scaling laws. fmax, fc.   Frequency dependence of seismic moment.  Strong motion data.  Spectral decay models and interpretation.

Ch. 5

12.

Seismotectonics. Fault rheology from seismic studies.  Depth-frequency relations for seismicity.  Strong motion studies.  Earthquake afterslip and the relation between coseismic and postseismic slip.   Fault heterogeneity, slip heterogeneity.

Ch. 6

13. 

Earthquake Prediction.  Earthquake triggering and fault interaction. Precursory phenomena.  Historical observations. 

Ch. 7

14. 

Student Project Presentations 

ACADEMIC INTEGRITY:  Cheating will not be tolerated under any circumstances.  Cheating is unfair to your classmates and an insult to curiosity and intellectual inquiry.  Anyone caught cheating will receive an automatic failing grade on that assignment/exam and will be reported to University officials.  General guidelines can be found in University Policies and Rules, p. 41. This course follows the http://www.ems.psu.edu/undergraduate/academic-advising/forms-and-procedures/academic-integrity. Penn State defines academic integrity as "the pursuit of scholarly activity in an open, honest and responsible manner." Academic integrity includes "a commitment not to engage in or tolerate acts of falsification, misrepresentation, or deception." In particular, the University defines plagiarism as "the fabrication of information and citations; submitting other's work from professional journals, books, articles, and papers; submission of other student's papers, lab results or project reports and representing the work as one's own." Penalties for violations of academic integrity may include course failure. To learn more, see Penn State's "Plagiarism Tutorial for Students."

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