1. Insights into Persistent Activity, Crater Formation & Phreatic to Phreatomagmatic Eruptions at Telica Volcano from Multiparameter Observations
- Author
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LaFemina, Peter, Saucier, Emilie, Chavarria, David, Feineman, Maureen, Geirsson, Halldor, Hanagan, Cassie, Higgins, Machel, Rodgers, Mel, Roman, Diana, Saballos, Armando, Strauch, Wilfried, and Tenorio, Virginia
- Abstract
Telica volcano is a persistently restless volcano with activity expressed as long-lived high-temperature fumaroles and magmatic degassing, high rates of background seismicity and frequent phreatic to phreatomagmatic eruptions. Two decades of geophysical, geochemical, and geologic observations indicate: 1) long-lived fumaroles cause hydrothermal alteration and collapse of crater walls, and deposition of debris in the crater; 2) decreases in gas flux, fumarole temperatures, remotely sensed thermal anomalies, and low-frequency seismicity prior to explosions and eruption of hydrothermal minerals and alteration products indicate sealing of the shallow hydrothermal system and conduit; and 3) eruption of a lava dome and ballistic blocks indicate viscous basaltic andesite magma in the conduit. Deposition of crater wall debris may seal the system at a shallow level but does not affect the deeper magmatic – hydrothermal system. Whereas the partial to complete sealing of the volcanic conduit occurs through the deposition of hydrothermal minerals, and the slow migration of viscous magma. These processes move the volcano from an open to a closed system, resulting in phreatic to phreatomagmatic explosions. We developed a numerical model to investigate near-field surface deformation measured by cGPS. Our model incorporates changes in permeability of the conduit due to mineralization, the accumulation of gas beneath the seal, and subsequent increase in pressure of the system driving surface deformation. Increase in pressure leads to failure of the seal and explosions. Improving our knowledge of this transition from an open to closed system is important for forecasting explosive activity at Telica and similar volcanic systems., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)
- Published
- 2023