These findings are contributing to a more accurate picture of the chaotic, dramatic 2006 eruption of Augustine Volcano. Graduate student researcher Valerie K. Wasser from the University of Alaska Fairbanks Geophysical Institute directed the study. Our new research published in the journal Geology on May 29 explores the science of crystal clots. These clots originate from a volcanic pyroclast named a bread-crust bomb. This study reveals how the interplay of different magma layers contributed to the violent eruption that disrupted air traffic and scattered ash across vast distances.
To some, the 2006 eruption was a minor geological footnote. It produced multiple explosive ash plumes that rose as high as 45,000 feet and deposited ash more than 70 miles away in Homer. This unprecedented analysis by Wasser sheds new light on how volcanic eruptions operate. Perhaps more intriguingly, it underscores the importance of pressure changes in magma chambers.
The Role of Crystal Analysis
The resulting Valerie K. Wasser crunched through a complex classification of curved versus straight plagioclase crystals of multiple growth histories deposited inside the bread-crust bomb. This intriguing volcanic rock is formed when a blob of super-sticky lava is violently blown into the atmosphere. As it cools it forms a mesmerizing structure that traps a wealth of geological knowledge.
In support of his thesis, Wasser focused on the crystals collected from many different areas inside Augustine’s magma chamber. She had a special interest in the plagioclase crystals. This would allow her to monitor these sediments over time, finding, among other things, a clear spike in calcium levels. The experimental work showed that the calcium content in plagioclase crystals grew up to 3.9% larger in size than under normal conditions. That report suggests that pressure was building in the magma chamber prior to the eruption.
Wasser’s discoveries emphasize how important the study of crystal growth patterns – petrography – can be to interpreting and understanding volcanic behavior. By piecing together these microscopic clues, scientists are able to decode the intricate mechanisms that trigger explosive volcanic eruptions.
Pressure Dynamics Behind the Eruption
The crux of Wasser’s research centers on how the addition of hot new magma into a reservoir of cooler, older magma heightened pressure within Augustine’s magma chamber. This spike in incoming pressure was responsible for an increase in pressure of 7.7 megapascals. That’s about 125 times the pressure of a typical home pressure cooker!
The ramifications of this pressure push are deep. Yet magma dynamics have the power to bring about eruptions by surprise. This brings enormous dangers to surrounding communities and commercial airline routes. The 2006 Augustine eruption demonstrated this risk for the first time. The ash plume upended air traffic and affected regions far beyond the immediate vicinity of the volcano.
Wasser’s approach for analyzing crystal composition could travel far past Augustine Volcano. It holds potential for producing post-eruption estimates of pre-eruption pressure changes at other arc volcanoes, aiding researchers in predicting future volcanic activity and enhancing safety measures for populations living near such geological features.
Collaborative Efforts and Future Research
Valerie K. Wasser’s research was bolstered by the collective power of community. Co-authors Pavel Izbekov, Taryn Lopez, Jamshid A. Moshrefzadeh, and Nathan Graham were instrumental in this endeavor. Their combined expertise contributed to a comprehensive study that not only illuminates the specific case of Augustine Volcano but offers tools for understanding similar volcanic systems worldwide.
Furthering this research ultimately lays the groundwork for better monitoring and predictive capabilities when it comes to volcanic eruptions. Knowing how magma chambers behave will be only one piece of the puzzle in making our eruption-related risks more manageable and protecting at-risk communities.