2112 P-axes can only be used as a proxy for σ1. The CVLD components observed are mostly just attributed to noise in the data, rather than tensile cracks which are not likely to happen in a mine setting. A group of several source mechanisms can be used to estimate the orientation of principal stresses (σ1, σ2 and σ3). A few procedures for this analysis have been proposed in the literature (Angelier, 1984; Gephart and Forsyth, 1984; Michael, 1984; and Harmsen and Rogers, 1986). However, to use those procedures, some assumptions are required: the stress field is homogeneous within the area of analysis, source mechanisms are slip type, seismic events are not controlled by a structure (slip planes need to have random orientations) and that the direction of slip is parallel to the direction of shear traction on the slip surface. It is worth noting that method by Vavryčuk, V. (2014) inverts jointly for stress and fault orientation. In practice, a large portion of the seismicity recorded at mines violates one or more of these assumptions. As such, applying these existing methodologies can only be applied to a carefully filtered subset of the seismic catalogue. To overcome this, Malovichko and Rigby (2024) proposed a novel technique in which clusters of seismicity with different patterns observed in mines (events associated with structures, or tunnels, or events attributed to random oriented planes of slip) can be used to invert for the far-field stress (or depending on the area selected, the total stress: in-situ stress + induced stress by a large excavation). The method is described in detail by Malovichko and Rigby (2024), but a brief summary is provided in the next section. 2. SIMS METHOD As shown in Figure 4, SIMS considers the following categories of events: • Events related to structures (or known weaknesses) in which one of the nodal planes matches the orientation of the weakness plane within some uncertainty in terms of the hypocenter location and the orientation of the nodal plane estimated. In this case, the direction of slip for the nodal plane needs to correlate direction of the shear traction in the weakness plane. Any angular difference can quantify the misfit between source mechanisms and the stress state. • Events close to tunnels with crush-type source mechanisms (with significant implosive component). In these cases, the convergence direction is controlled by the maximum principal stress in the plane orthogonal to the tunnel’s axis. Therefore, in this case, the misfit between the P-axes calculated and
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