MICROSTRUCTURES AND ROCK RHEOLOGY
Discussion Session 1: Brittle fault rocks and the brittle-ductile transition
In this discussion session we focus on the field and micro-scale characteristics of brittle fault rocks, and on how
these characteristics may significantly affect the frictional properties of rocks such that they deviate from the
classic Byerlee’s Law. Five of you will be assigned to present one paper each to the class, but you are all expected
to read each paper and to participate in the discussion. In your reading you should focus on, and jot down notes on
the following questions:
1.
2.
3.
4.
5.
What is the overarching scientific problem the authors are trying to address and why is it important?
What kind of data do the authors collect and what methods to they use?
How do the authors interpret their data? Do you think the interpretations are reasonable and supported
by the data presented?
What are the implications of the authors results for other disciplines? (e.g. seismology, earthquake
mechanics)
Are there similar themes or approaches between two or more of the five papers? Are there discrepancies
between two or more papers?
Also write a single sentence summarizing the main point of each paper.
Papers to read:
Chester, FM. 1986. “Implications for Mechanical Properties of Brittle Faults From Observations of the Punchbowl
Fault Zone, California.” Pure and Applied Geophysics.
Collettini, Cristiano, A Niemeijer, C Viti, and C Marone. 2009. “Fault Zone Fabric and Fault Weakness.” Nature
462 (7275): 907–910.
di Toro, G, T Hirose, S Nielsen, G Pennacchioni, and T Shimamoto. 2006. “Natural and Experimental Evidence of
Melt Lubrication of Faults During Earthquakes.” Science 311 (5761): 647.
Lin, A, T Maruyama, S Aaron, K Michibayashi, A Camacho, and K Kano. 2005. “Propagation of Seismic Slip From
Brittle to Ductile Crust: Evidence From Pseudotachylyte of the Woodroffe Thrust, Central Australia.”
Tectonophysics 402 (1-4): 21–35.
Rowe, Christen D, J Casey Moore, Francesca Meneghini, and Alexander W McKeirnan. 2005. “Large-Scale
Pseudotachylytes and Fluidized Cataclasites From an Ancient Subduction Thrust Fault.” Geology 33 (12): 937.
doi:10.1130/G21856.1.