Physical Sciences and Mathematics Commons^™

Controls On The Frequency Content Of Near-Source Infrasound At An Open-Vent Volcano (Villarrica, Chile), Bryan Blake Rosenblatt

Boise State University Theses and Dissertations

The acoustic signals from open-vent volcanoes can contain specific information related to that volcano’s eruption dynamics and future activity. Thus, studying a specific volcano’s acoustics may provide critical warning mechanisms, signaling impending eruptions. Villarrica volcano, located in southern Chile, has an active lava lake that produces continuous infrasound with spectral peaks near 1 Hz and excursions of +/- ~0.2 Hz. The infrasound’s frequency content reveals key volcanic properties such as eruption style and crater shape. Leading up to Villarrica’s most recent paroxysm in 2015, infrasound spectral changes coincided with and indicated a rise in Villarrica’s lava lake level. As such, …

Pressure Waves And Tephra Dispersal From Volcanic Explosions: Models, Observations, And Instrumentation, Jacob Fortner Anderson

Boise State University Theses and Dissertations

Real-time study of erupting vents is important for both monitoring and scientific purposes; because direct in-situ study of erupting vents is impractical, our best tools for studying eruptions in real time involve monitoring eruptive products and waves that travel far from the volcano. The atmosphere is a particularly advantageous medium for studying propagation and transport of volcanic waves and products: acoustic waves pass through it with minimal scattering, particles follow predictable trajectories, and the atmospheric structure that affects both is well-monitored. Analyses of acoustic waves and tephra deposits can provide important information on eruptions including total explosive energy, volume, and …

Volcano Infrasound Monitoring With Applications For Statistical Forecasting Of Explosions At Sakurajima (Japan), Matthew R. Vonlintig

Boise State University Theses and Dissertations

Volcanic eruptions are powerful natural phenomena that often occur unpredictably in time and magnitude. Nearby communities are put at risk during volcanic unrest; however, when hazards are well understood and clearly defined risk can be mitigated. This thesis addresses the problem of forecasting the likelihood of future explosive volcanic behavior by monitoring ongoing eruptive history with infrasound. I parameterize inter-event temporal behavior to determine the eruption controlling processes is material failure opposed to changes in magma and volatile supply.

I analyze data from Sakurajima, a type-example open volcano, using two local (4 km from the vent) microphone arrays, which recorded …

Tracking And Characterization Of Moving Acoustic Sources Using An Infrasound Array At Volcán Santiaguito, Guatemala, Brian R. Terbush

Boise State University Theses and Dissertations

Active volcanic processes produce large amounts of acoustic energy within the infrasound band (0-20 Hz). Infrasound-sensitive microphones are often installed in addition to other forms of volcano monitoring equipment to increase the ability to remotely detect volcanic activity. In this study, an array of microphones was deployed without any additional sensor types for 36 hours at Santiaguito, Guatemala, to test the detection capabilities of a standalone microphone array. Array processing was applied to the recorded data, through frequency-domain beamforming and calculating a Fisher statistic (F). A changing F-threshold value was applied to differentiate between desired detections, or …