Analysis of Volcanic Seismicity Clustering Using Data of the 2006 Eruption of Alaska's Augustine Volcano

The paper is devoted to the analysis of spatiotemporal grouping of volcanic seismicity events confined to the Augustine volcano in Alaska. Heterogeneity of the seismic regime in the final preparation stage of the 2006 eruption was revealed relative to the regimes during periods of calm and the initial stage of seismic activation. This final stage is presumably associated with the process of magma intrusion into the dike, upon completion of which the eruption began. A detailed analysis of the seismicity of this phase revealed two seismic regimes that differ in their main characteristics. One of the regimes is similar in parameters to that observed at the early preparation stage – a high value of the magnitude-frequency distribution slope parameter ( -value) and a low degree of clustering. The second has a lower b-value and represents a series of clusters ending with the strongest event in the series, followed by a lull.