Methods For Monitoring And Forecasting Volcanic Hazards And Eruptions Using Seismology And Other Geophysical Data

Abstract

Recent eruptions of three Alaskan volcanoes have provided the opportunity to study the relationships between seismicity and volcanic hazards and other phenomena. The ability to forecast or track volcanic activity through seismicity is important because seismic monitoring can be done in real time, 24 hours a day, regardless of weather, dangerous conditions or distance. To this end, the eruptions of Veniaminof in 2005, Augustine Volcano in 2006, and Redoubt Volcano in 2009, have been studied with the focus on understanding how seismic recordings and measurements are related to physical characteristics of eruption phenomena. Positive correlations were seen in relationships between ash plume heights at Veniaminof and their accompanying seismic magnitudes, and sizes and directions of rockfalls and block-and-ash flows at Augustine with seismic amplitude ratios and magnitudes. The relationship of rockfall occurrences in background years was also correlated with seasons and weather patterns, making easier the identification of rockfall increases that may be eruption precursors. Volcanic tremor, which frequently occurs accompanying volcanic eruptions, is studied during the Redoubt eruption, through the generation of duration-amplitude plots, and the potential for a new forecasting or monitoring tool is discussed.