high velocity frictional properties of alpine fault rocks mechanical data microstructural analysis and implications for rupture propagation

High-velocity frictional properties of Alpine Fault rocks: Mechanical data,microstructural analysis, and implications for rupture propagation Carolyn Boulton, Lu Yao, Daniel R.. This is

High-velocity frictional properties of Alpine Fault rocks: Mechanical data,

microstructural analysis, and implications for rupture propagation

Carolyn Boulton, Lu Yao, Daniel R Faulkner, John Townend, Virginia G Toy, Rupert

Sutherland, Shengli Ma, Toshihiko Shimamoto

PII: S0191-8141(17)30040-8

DOI: 10.1016/j.jsg.2017.02.003

Reference: SG 3445

To appear in: Journal of Structural Geology

Received Date: 7 August 2016

Revised Date: 30 January 2017

Accepted Date: 9 February 2017

Please cite this article as: Boulton, C., Yao, L., Faulkner, D.R., Townend, J., Toy, V.G., Sutherland, R., Ma, S., Shimamoto, T., High-velocity frictional properties of Alpine Fault rocks: Mechanical data,

microstructural analysis, and implications for rupture propagation, Journal of Structural Geology (2017),

doi: 10.1016/j.jsg.2017.02.003.

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Table 1 Quantitative X-ray diffraction data

Hole Depth/Sample Lithology Quartz K Feldspar Plagioclase Calcite Kaolinite Smectite White mica Chlorite Serpentine c Talc % Phyllosilicates

Table 2 Summary of high-velocity friction experiments and results.

Experiment Material Lithology Dry/Wet sN (MPa) veq (m/s) d eq (m) µp corrected µss corrected d w (m) E G (MJ/m 2 )

Cemented cataclasite

Active river bed

Australian Plate

Pacific Plate

C

DFDP-1 Gaunt Creek

PSZ gouge

D E

F Gravel 1

DFDP1B 128.80 m DFDP1B 128.44 m

Qtz Qtz

LHV279 1A90.62m DRY LHV280 1B128.80m DRY

LHV262 HkC PSZ DRY LHV272 HkC PSZ DRY

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

LHV278 GC Scarp PSZ WET LHV288 1B144.04m WET

LHV289 HkC PSZ WET

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

LHV284 1A86.41m WET LHV285 1A90.32m WET

LHV286 1A90.62m WET LHV287 1B128.80m WET

LHV582 1B128.44m WET v=1 m/s, v=1 mm/s

0.9 1 1.1 1.2 1.3 1.4 1.5 1.6

LHV574 LHV583

LHV581

0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7

LHV579 LHV584

WET smectitic phyllosilicate-rich

DRY smectitic phyllosilicate-rich

0 0.2 0.4 0.6 0.8 1 1.2 1.4

LHV279 LHV286

LHV277 LHV278

LHV574 LHV579

LHV280 LHV287

LHV283 LHV288

LHV272 LHV289

symmetry axis

heat sources

400 450

150 250

350 300 455

B

0 5 10 15 20

distance from axis (mm)

Figure 7

0.750 1.0

1.126 1.501

LHV574 DRY

LHV583 DRY

LHV581 DRY

Figure 10

Figure 11

• Alpine Fault rocks exhibit weak friction in high-velocity experiments

• Wet smectitic gouges have the lowest peak friction and steady state friction

values

• Rupture propagation through wet smectitic gouges is energetically favorable

• Wet experimental gouge microstructures resemble natural gouge

microstructures