Periods of heightened volcanic seismicity across the Aleutian Arc, Alaska

Abstract

"Data from the Alaska Volcano Observatory and Alaska Earthquake Information Center catalogs are applied to four research initiatives. In Chapter 1, the distinction between mainshock-aftershock sequences and swarms is made on the basis of how the total elastic energy is partitioned between the largest and smaller magnitude earthquakes. Chapter 2 establishes that multiplets are ubiquitous to periods of heightened volcano-seismicity across the Aleutian Islands and argues that they arise from the diffusion of heat and/ or pore fluids through the system and not from an increase in stress. The attributes of the 2008 Kasatochi eruption and pre-eruptive swarm are discussed in Chapter 3. Cross-correlation techniques are employed to root out additional waveforms that were either below the threshold of the detection or location algorithms used. The onset time of the pre-eruptive swarm is redefined and its temporal development more fully characterized. Chapter 4 integrates seismic and acoustic data to analyze the Continuous Phase of the 2006 eruption of Augustine Volcano. The Continuous Phase is shown to be a scaled-down version of the Explosive Phase. What was perceived by remote sensing observations as a continuous, unperturbed eruption is shown here to be a rapid succession of discrete blasts"--Leaf iii