Dynamic Shear Rupture in Frictional Interfaces: Speeds, Directionality, and Modes
The goal in designing dynamic frictional experiments simulating earthquake rupture has been to create a testing environment or platform which could reproduce some of the basic physics governing the rupture dynamics of crustal earthquakes while preserving enough simplicity so that clear conclusions can be obtained by pure observation. In this chapter, we first review past and recent experimental work on dynamic shear rupture propagation along frictional interfaces. The early experimental techniques are discussed in relation to recent experimental simulations of earthquakes which feature advanced diagnostics of high temporal and spatial resolution. The high-resolution instrumentation enables direct comparison between the experiments and data recorded during natural earthquakes. The experimental results presented in this chapter are examined in light of seismological observations related to various natural large rupture events and of recent theoretical and numerical development in the understanding of frictional rupture. In particular, the physics and conditions leading to phenomena such as supershear rupture growth, sub-Rayleigh to supershear rupture transition, and rupture directionality in inhomogeneous systems are discussed in detail. Finally, experiments demonstrating the attainability of various rupture modes (crack-like, pulse-like, and mixed) are presented and discussed in relation to theoretical and numerical predictions.
© 2007 Elsevier B.V. This chapter is reproduced from the previous edition, Volume 4, pp. 153–192. The authors gratefully acknowledge the support of NSF (Grant EAR 0207873), the US Department of Energy (Grant DE-FG52-06NA 26209), and the consistent support of the Office of Naval Research (Grant N00014-03-1-0435) and MURI (Grant N000140610730) through Dr. Y.D.S. Rajapakse, Program Manager.