Abstract
Seismic observations have long been an essential part of seismic event monitoring, especially for discriminating between naturally occurring earthquakes and man-made explosions. Among many analytical methods, the amplitude ratio between seismic P and S body waves have been shown to be an effective discriminant at teleseismic and regional distances. However, discriminating low yield seismic events (M<4) recorded at local distances (<200 km) is an area of active research. In this study, we analyze data from a range of magnitude 1-3 events, including earthquakes, mining-induced events (rock bursts, collapses and pure slip) and explosions recorded on broadband stations at local distances within and adjacent to the Kiruna iron ore mine and Paervie fault in northern Sweden. After correcting instrument effects, we visually pick P- and S-wave arrival times and measure the P and S wave amplitudes across several frequency bands. Before determining the P/S ratio, we apply a magnitude and distance amplitude correction (MDAC) to the measured P and S amplitudes. We analyze, quantify, and compare the patterns of MDAC-corrected ratios for blasts, mining-induced events, and earthquakes and search for distinguishable patterns. Preliminary results of the average log(P/S) values of a source type suggest that at passbands of 4-6 Hz and above blasts can be distinguished from other event types.