Comparing the performance of stacking-based methods for microearthquake location: a case study from the Burträsk fault, northern Sweden

SUMMARY Traditional earthquake location relying on first arrival picking is challenging for microseismic events with low signal-to-noise ratio. Over the past years, alternative procedures have been explored based idea of migrating energy an back into its source position by stacking along theoretical traveltime curves. To avoid destructive interference signals opposite polarity, it common to transform input positive time-series. Stacking-based has successfully applied at various scales, but existing studies differ considerably in choice characteristic function, amount pre-processing and phases used analysis. We use a data set 62 natural microearthquakes recorded 2-D seismic array 145 vertical geophones across glacially triggered Burträsk fault compare performance five commonly functions: noise filtered seismograms semblance, envelope, short-term average/long-term average ratio kurtosis gradient seismograms. obtain best results combined P- S-wave using polarity-sensitive that or semblance. In contrast, absolute functions often fail align properly, yielding biased estimates. Moreover, we observe success procedure very sensitive suppression signal shaping prior stacking. Our study demonstrates usefulness including lower quality improve Furthermore, our illustrate benefits retaining phase information accuracy suppression. ensure optimal results, recommend carefully test different each new set. Despite suboptimal geometry, good locations most within ?30–40 km survey are consistent image trace from earlier reflection survey.