ABSTRACT:

The scalar characteristics (ie stress magnitudes alone) from ca. 200 Western Australian School of Mines Acoustic Emission (WASM AE) rock stress tensor determinations are compared with those compiled in an Earth Rock Stress Tensor Database. The two data sets comprise results obtained from different geologic and geodynamic regimes within different continents in the upper 3 km of Earth's crust. Importantly, the data sets are restricted to results from techniques that attempt to measure, without a priori assumption, the complete rock stress tensor and are presented as reported in the literature, without prejudice or censorship.

1 INTRODUCTION

The WASM AE stress measurement technique (Villaescusa et al., 2002), samples the Kaiser Effect (Kaiser, 1953, Holcomb, 1993) in 6 independent orientations from oriented sub-cores taken from oriented master core. To date, over 200WASMAE stress tensor determinations have nowbeen conducted from near the surface (eg. Villaescusa et al., 2002) to a depth over 2.5 km (eg. Villaescusa et al., 2009a). Detailed laboratory investigations have been conducted on the technique at the Advanced Institute of Science and Technology, Tsukuba, Japan (Villaescusa et al., 2009b) and further laboratory investigations have been commissioned from Sandia National Research Laboratories, USA. Detailed site investigations have been conducted at mine sites in Australia (eg. Windsor, 2005, 2006, 2007 and Windsor et al., 2007), Chile (Windsor et al., 2006a, 2006b) and Peru (Windsor, 2009a) in attempts to reconcile the stress measurement results with local conditions of rock strain, rock structure and rock strength. Here, we record the scalar characteristics (ie stress magnitudes alone) from ca. 200WASMAE rock stress tensor determinations obtained from different geological, geodynamic regimes from different continents and compare these to those compiled in an Earth Rock Stress Tensor Database (ERSTD) (Windsor, 2009b). The data are presented as reported, without prejudice or censorship.

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