Abstract
We use infrasound waves generated during eruptions of Volcán Tungurahua (Ecuador) to study both, changing atmospheric conditions and volcanic source characteristics. Analyzed infrasound data were recorded for a 32-month period by a five-station network located within 6.5 km from the vent. We use cross-network correlation to quantify the recurrent eruptive behavior of Tungurahua and results are corroborated by reports from the Ecuadorian monitoring agency. Cross-network lag times vary over short time periods (minutes to days) when vent location is stable and attribute these variations to changes in atmospheric structure. Assuming a fixed source location, we invert for average air temperatures and winds in Tungurahua's vicinity (< 6.5 km) and find evidence for diurnal and semidiurnal tropospheric tides. We also use cross-network correlation lag times to compute infrasound source positions with resolutions of ~ 11.6 m, taking into account coarse NOAA atmospheric models for local winds and temperatures. Variable infrasound-derived source locations suggest source migration during the 32 months of analyzed data. Such source position variability is expected following energetic eruptions that destructively altered the crater/vent morphology as confirmed by imagery obtained during regular overflights.
| Original language | English |
|---|---|
| Pages (from-to) | 205-216 |
| Number of pages | 12 |
| Journal | Journal of Volcanology and Geothermal Research |
| Volume | 349 |
| DOIs | |
| State | Published - 1 Jan 2018 |
Bibliographical note
Publisher Copyright:© 2017 Elsevier B.V.
Funding
We would like to thank to the people that installed the infrasound network and continuously supervise it. These people include to Hiroyuki Kumagai, Pablo Palacios, Jorge Cordova, Wilson Enriquez, Alexandra Alvarado, Daniel Pacheco, Patricia Mothes, among others. In addition, we are grateful to Jacob Anderson and Alexander Miller for their continuous comments and discussion during the preparation of this study as well as to David Fee and one anonymous reviewer for their thoughtful comments that helped to improve this manuscript. Finally, we are in debt with Benjamin Bernard for his readiness on sharing audio-visual material that enhanced the discussion of Volcán Tungurahua's eruptive dynamics. This work was made possible with support from the National Science Foundation EAR grant 1151662 .
| Funders | Funder number |
|---|---|
| National Science Foundation | 1151662 |
Keywords
- Atmospheric tides
- Crater morphology changes
- Infrasound source localization
- Volcano infrasound
- Volcán Tungurahua
- Wind velocities and air temperatures