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MacQueen, Patricia
Delgado, Francisco
Reath, Kevin A.
Pritchard, Matthew E.
Bagnardi, Marco
Milillo, Pietro
Lundgren, Paul
Macedo Sánchez, Orlando
Aguilar Purhuaya, Víctor
Ortega Gonzáles, Mayra Alexandra
Anccasi Figueroa, Rosa María
Lazarte Zerpa, Ivonne Alejandra
Miranda Cruz, Rafael
Volcán Sabancaya
MacQueen P., Delgado F., Reath K., Pritchard M., Bagnardi M., Milillo P., Lundgren P., Macedo O., Aguilar V., Ortega M., Anccasi R., Lazarte I. & Miranda, R. (2020). Volcano-tectonic interactions at Sabancaya volcano, Peru: eruptions, magmatic inflation, moderate earthquakes, and fault creep. Journal of Geophysical Research: Solid Earth, 125(5): 33 p.
61 páginas
We present evidence of volcano-tectonic interactions at Sabancaya volcano that we relate to episodic magma injection and high regional fluid pore pressures. We present a surface deformation time series at Sabancaya including observations from ERS-1/2, Envisat, Sentinel-1, COSMO-SkyMed, and TerraSAR-X that spans June 1992 to February 2019. These data show deep-seated inflation northwest of Sabancaya from 1992–1997 and 2013–2019, as well as creep and rupture on multiple faults. Afterslip on the Mojopampa fault following a 2013 MW 5.9 earthquake is anomalously long lived, continuing for at least 6 years. The best fit fault plane for the afterslip is right-lateral motion on an EW striking fault at 1 km depth. We also model surface deformation from two 2017 earthquakes (MW 4.4 and MW 5.2) on unnamed faults, for which the best fit models are NW striking normal faults at 1–2 km depth. Our best fit model for a magmatic inflation source (13 km depth, volume change of 0.04 to 0.05 km3 yr−1) induces positive Coulomb static stress changes on these modeled fault planes. Comparing these deformation results with evidence from satellite thermal and degassing data, field observations, and seismic records, we interpret strong pre-eruptive seismicity at Sabancaya as a consequence of magmatic intrusions destabilizing tectonic faults critically stressed by regionally high fluid pressures. High fluid pressure likely also promotes fault creep driven by static stress transfer from the inflation source. We speculate that combining high pore fluid pressures with sufficiently large, offset magmatic inflation can promote strong earthquakes during volcanic unrest.
American Geophysical Union
Repositorio Institucional INGEMMET
Instituto Geológico, Minero y Metalúrgico – INGEMMET
Erupciones volcánicas
Sensores remotos
Volcano-tectonic interactions at Sabancaya volcano, Peru: eruptions, magmatic inflation, moderate earthquakes, and fault creep
Journal of Geophysical Research: Solid Earth
Peer reviewed
Journal of Geophysical Research: Solid Earth, vol. 125, n, 5, 2020

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