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title of the thesis - Department of Geology - Queen's University

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3.2.1.2 Seismic Energy (E o ) and Seismic Moment (M o )<br />

The seismic moment (M o ) is a measure <strong>of</strong> event size and strength. Seismic energy, E o , is a<br />

measure <strong>of</strong> <strong>the</strong> total elastic energy radiated during fracture and frictional sliding (Gibowicz and<br />

Kijko, 1994; Mendecki, 1997).<br />

Microseismic events have lower energies and seismic moments compared to blasts or<br />

macroseismic events. This is also a spatial trend: events immediately west <strong>of</strong> <strong>the</strong> excavation in<br />

proximity to production blasts have high event energies and seismic moments (Fig. 3.4). Events<br />

located to <strong>the</strong> southwest <strong>of</strong> <strong>the</strong> excavation have lower energies compared to blast-related events<br />

but higher energies as compared to <strong>the</strong> remaining events south to sou<strong>the</strong>ast <strong>of</strong> <strong>the</strong> excavation.<br />

Figure 3.4: Map <strong>of</strong> <strong>the</strong> 7400 Level showing <strong>the</strong> distribution microseismic event energy. The excavated<br />

area is outlined in black. The colour <strong>of</strong> <strong>the</strong> event epicenters corresponds to event energy. The colour scale<br />

is logarithmic and represents energy in Joules.<br />

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