Local, Regional, and Remote Seismo‐acoustic Observations of the April 2015 VEI 4 Eruption of Calbuco Volcano, Chile

Abstract

The two major explosive phases of the 22–23 April 2015 eruption of Calbuco volcano, Chile, produced powerful seismicity and infrasound. The eruption was recorded on seismo‐acoustic stations out to 1,540 km and on five stations (IS02, IS08, IS09, IS27, and IS49) of the International Monitoring System (IMS) infrasound network at distances from 1,525 to 5,122 km. The remote IMS infrasound stations provide an accurate explosion chronology consistent with the regional and local seismo‐acoustic data and with previous studies of lightning and plume observations. We use the IMS network to detect and locate the eruption signals using a brute‐force, grid‐search, cross‐bearings approach. After incorporating azimuth deviation corrections from stratospheric crosswinds using 3‐D ray tracing, the estimated source location is 172 km from true. This case study highlights the significant capability of the IMS infrasound network to provide automated detection, characterization, and timing estimates of global explosive volcanic activity. Augmenting the IMS with regional seismo‐acoustic networks will dramatically enhance volcanic signal detection, reduce latency, and improve discrimination capability.

Ionospheric Detection of Natural Hazards

“…One can see that for the first eruption, the source of the ionospheric perturbation can be localized sufficiently well, as the position of the eruption was estimated within ±1-2°of latitude and/or longitude. From their method, Shults et al (2016) calculated the time of the first eruption's onset between 21.07 UT and 21.29 UT; these ionosphere-based results were close to the onset time calculated from seismometers (21.07 UT) and to that from infrasound stations (21.16 UT ± 0.12 hr; Matoza et al, 2018).…”

Investigating Spectral Distortion of Local Volcano Infrasound by Nonlinear Propagation at Sakurajima Volcano, Japan

“…Recordings of volcano infrasound at regional (15–250 km) and global ( 250 km) distances can be used to detect, locate, and characterize remote eruptions (e.g., Dabrowa et al, ; Matoza et al, , , ). At these scales, acoustic wavefield distortion by propagation through the dynamic atmosphere is significant and constitutes an active area of research (Assink et al, ; Fee et al, ; Green et al, ; Matoza et al, ; Waxler & Assink, ). Early work in this field made the assumption that recordings at local distances ( 15 km) were directly representative of the source process (e.g., Morrissey & Chouet, ); however, it has now been established that near‐vent propagation dynamics influence the acoustic wavefield (Fee & Garces, ; Kim & Lees, ; Kim et al, ; Kim & Lees, ; Lacanna & Ripepe, ; Matoza et al, ).…”

“…Visual observations of wavefronts above erupting vents imply near‐source shock wave formation (Ishihara, ; Yokoo & Ishihara, ), but these waves do not necessarily indicate supersonic sources (Genco et al, ). Nonlinear propagation has been proposed as a possible explanation for asymmetric infrasound waveforms, which are commonly observed at volcanoes worldwide (e.g., Anderson et al, ; Fee et al, ; Marchetti et al, ; Matoza et al, ; Medici et al, ). However, this phenomenon can alternatively be explained with linear propagation and crater rim diffraction (Kim & Lees, ) or fluid flow at the source (Brogi et al, ).…”

Remote Detection and Location of Explosive Volcanism in Alaska With the EarthScope Transportable Array

“…Global infrasound networks have been shown to be effective at detecting relatively violent eruptions, even in remote locations (Dabrowa et al, ; Evers & Haak, ; Fee, Steffke, & Garcés, ; Fee et al, ; Le Pichon et al, ; Liszka & Garcés, ; Matoza et al, ; Matoza et al, ; Matoza, Le Pichon , et al, ; Matoza, Vergoz, et al, ). Local infrasound networks (sources <15 km distant), however, are better placed for identifying smaller explosions, degassing, or effusive behavior within a limited radius (e.g., De Angelis et al, ; Fee et al, ; Fee, Garcés, et al, ; Johnson et al, ; Jolly et al, ; Matoza et al, ; Petersen & McNutt, ).…”

“…Regional infrasound coverage on a similar scale to the TA is currently limited to combinations of national networks such as those in the Euro‐Mediterranean region (Tailpied et al, ). Other national infrasound networks include those in Iceland (Jónsdóttir et al, ), Japan (Batubara et al, ), Chile (Matoza et al, ), and Singapore (Perttu et al, ).…”