Subsurface anatomy of the Irazú–Turrialba volcanic complex, inferred from the integration of local and ambient seismic tomographic methods
Fecha
2024
Tipo
artículo original
Autores
Jiwani Brown, Elliot Amir
Koulakov, Ivan
Muñoz Burbano, Francisco
Pacheco Alvarado, Javier Francisco
Mora Fernández, Mauricio
Savard, Geneviève
Lupi, Matteo
Título de la revista
ISSN de la revista
Título del volumen
Editor
Oxford University Press (OUP)
Resumen
Irazú and Turrialba are a twin volcanic complex that marks a distinct stop in volcanism along the Central America volcanic arc. We present a new traveltime velocity model of the crust beneath Iraz ´ u and Turrialba volcanoes, Costa Rica, and interpret it considering the results of previous ambient noise tomographic inversions. Data were acquired by a temporary seismic network during a period of low activity of the Iraz ´ u–Turrialba volcanic complex in 2018–2019. Beneath the Iraz ´ u volcano, we observe low P -wave velocities ( V P = 5 km s −1 ) and low velocity ratios ( V P / V S = 1.6). In contrast, below the Turrialba volcano, we observe low S -wav e v elocities ( V S = 3 km s −1 ) and a high V P / V S ( = 1.85) anomaly. We found that locations of low V P and V S anomalies ( −15 %) correspond well with shear wave velocity anomalies retrieved from ambient noise tomography. At shallower depths, we observe high V P and V S anomalies ( + 15 %) located between the summits of the volcanoes. Subvertical velocity anomalies are also observed at greater depths, with high V P and V S anomalies appearing at the lower limits of our models. We propose a complex structure of an intermediate magmatic reservoir, presenting multiphase fluid states of a liquid-to-gas transition beneath Iraz ´ u and a juvenile store of magmatic fluid beneath Turrialba, while shallow fluid transport provides evidence of magmatic–hydrothermal interactions.
Descripción
Palabras clave
EARTHQUAKE GROUND MOTIONS, SEISMIC TOMOGRAPHY, VOLCANIC ARC PROCESSES, MAGMA CHAMBER, PHYSICS OF MAGMA, MAGMA BODIES