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Full-Text Articles in Physical Sciences and Mathematics
Volcano Infrasound: Progress And Future Directions, Jacob F. Anderson, Jeffrey B. Johnson
Volcano Infrasound: Progress And Future Directions, Jacob F. Anderson, Jeffrey B. Johnson
Geosciences Faculty Publications and Presentations
Over the past two decades (2000–2020), volcano infrasound (acoustic waves with frequencies less than 20 Hz propagating in the atmosphere) has evolved from an area of academic research to a useful monitoring tool. As a result, infrasound is routinely used by volcano observatories around the world to detect, locate, and characterize volcanic activity. It is particularly useful in confirming subaerial activity and monitoring remote eruptions, and it has shown promise in forecasting paroxysmal activity at open-vent systems. Fundamental research on volcano infrasound is providing substantial new insights on eruption dynamics and volcanic processes and will continue to do so over …
Acoustic And Seismic Fields Of Hydraulic Jumps At Varying Froude Numbers, Timothy J. Ronan, Jonathan M. Lees, T. Dylan Mikesell, Jacob F. Anderson, Jeffrey B. Johnson
Acoustic And Seismic Fields Of Hydraulic Jumps At Varying Froude Numbers, Timothy J. Ronan, Jonathan M. Lees, T. Dylan Mikesell, Jacob F. Anderson, Jeffrey B. Johnson
Geosciences Faculty Publications and Presentations
Mechanisms that produce seismic and acoustic wavefields near rivers are poorly understood because of a lack of observations relating temporally dependent river conditions to the near-river seismoacoustic fields. This controlled study at the Harry W. Morrison Dam (HWMD) on the Boise River, Idaho, explores how temporal variation in fluvial systems affects surrounding acoustic and seismic fields. Adjusting the configuration of the HWMD changed the river bathymetry and therefore the form of the standing wave below the dam. The HWMD was adjusted to generate four distinct wave regimes that were parameterized through their dimensionless Froude numbers (Fr) and …
Mapping Thunder Sources By Inverting Acoustic And Electromagnetic Observations, J. F. Anderson, J. B. Johnson, R. O. Arechiga, R. J. Thomas
Mapping Thunder Sources By Inverting Acoustic And Electromagnetic Observations, J. F. Anderson, J. B. Johnson, R. O. Arechiga, R. J. Thomas
Geosciences Faculty Publications and Presentations
We present a new method of locating current flow in lightning strikes by inversion of thunder recordings constrained by Lightning Mapping Array observations. First, radio frequency (RF) pulses are connected to reconstruct conductive channels created by leaders. Then, acoustic signals that would be produced by current flow through each channel are forward modeled. The recorded thunder is considered to consist of a weighted superposition of these acoustic signals. We calculate the posterior distribution of acoustic source energy for each channel with a Markov Chain Monte Carlo inversion that fits power envelopes of modeled and recorded thunder; these results show which …