Local Volcano Infrasound and Source Localization Investigated by 3D Simulation

Introduction to an Open Community Infrasound Dataset from the Actively Erupting Sakurajima Volcano, Japan

“…The difference spectra were calculated on a log scale between 0.1 and 20 Hz and were smoothed to emphasize the overall trends in spectral levels. ARI is used as the reference station because it appears to have the least amount of propagation effects related to topography (Kim and Lees, 2014). HAR and SVO are reduced 10-15 dB down relative to the reference below 1 Hz and reduced more than 20 dB above 5 Hz.…”

“…The significant topography around Sakurajima is the likely cause of the waveform variability between stations (e.g., Kim and Lees, 2014). Figure 9a shows a 3D perspective map of Sakurajima and the infrasound deployment, whereas Figure 9b shows the station-vent profiles.…”

“…8 and 9). Manuscripts in this Focus Section by Kim and Lees (2014), McKee et al (2014), andYokoo et al (2014) discuss acoustic propagation and topographic effects at Sakurajima in more detail. They complement recent studies that have noted the significant effect of topography and diffraction on acoustic propagation from volcanoes (e.g., Kim and Lees, 2011;Lacanna and Ripepe, 2012), including a study by Lacanna et al (2014) on regional (tens of kilometers) infrasound propagation from Sakurajima in which wind is shown to play an important role.…”

“…Johnson and Miller (2014) apply waveform modeling to estimate volume of erupted material associated with the Sakurajima explosions. Kim and Lees (2014) use novel graphical processing unit-based finite difference time domain processing to investigate 3D infrasound propagation and source localization. McKee et al (2014) test the network semblance method on acoustic source localization at Sakurajima and use it to help characterize volcanic activity.…”

Application of the Monopole Source to Quantify Explosive Flux during Vulcanian Explosions at Sakurajima Volcano (Japan)

“…Waveform variability across an infrasound network was highlighted by Fee et al (2014;this Focus Section), who state that waveform shape is affected by intervening topography, which diffracts sound waves around the crater rim and also above and over the edifice. Primary effects of topography are investigated with finite difference time domain techniques such as those presented by Kim et al (2014;this Focus Section), who found that topography influences waveform character most significantly at stations beyond the line-of-sight of the Showa Crater. Other studies, such as those at Tungurahua (Ecuador) by Kim et al (2012), suggest that crater topography near to the vent can induce an asymmetric acoustic radiation pattern that explains the variable sound intensities recorded on the infrasound network there.…”