Earthquake source properties from instrumented laboratory stick-slip

By: , and 
Edited by: Marion Y. ThomasThomas M. Mitchell, and Harsha S. Bhat

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Abstract

Stick-slip experiments were performed to determine the influence of the testing apparatus on source properties, develop methods to relate stick-slip to natural earthquakes and examine the hypothesis of McGarr [2012] that the product of stiffness, k, and slip duration, Δt, is scale-independent and the same order as for earthquakes. The experiments use the double-direct shear geometry, Sierra White granite at 2 MPa normal stress and a remote slip rate of 0.2 µm/sec. To determine apparatus effects, disc springs were added to the loading column to vary k. Duration, slip, slip rate, and stress drop decrease with increasing k, consistent with a spring-block slider model. However, neither for the data nor model is kΔt constant; this results from varying stiffness at fixed scale.

In contrast, additional analysis of laboratory stick-slip studies from a range of standard testing apparatuses is consistent with McGarr's hypothesis. kΔt is scale-independent, similar to that of earthquakes, equivalent to the ratio of static stress drop to average slip velocity, and similar to the ratio of shear modulus to wavespeed of rock. These properties result from conducting experiments over a range of sample sizes, using rock samples with the same elastic properties as the Earth, and scale-independent design practices.

Additional publication details

Publication type Book chapter
Publication Subtype Book Chapter
Title Earthquake source properties from instrumented laboratory stick-slip
Chapter 8
ISBN 9781119156888
DOI 10.1002/9781119156895.ch8
Year Published 2017
Language English
Publisher Wiley
Contributing office(s) Earthquake Science Center
Description 19 p.
Larger Work Type Book
Larger Work Subtype Monograph
Larger Work Title Fault zone dynamic processes: Evolution of fault properties during seismic rupture
First page 151
Last page 169