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Long period seismic source characterization at Popocatépetl volcano, Mexico
Author(s) -
ArciniegaCeballos Alejandra,
Dawson Phillip,
Chouet Bernard A.
Publication year - 2012
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2012gl053494
Subject(s) - geology , seismology , induced seismicity , impact crater , volcano , magma , period (music) , point source , hydrothermal circulation , volcanism , petrology , geophysics , tectonics , physics , astronomy , acoustics , optics
The seismicity of Popocatépetl is dominated by long‐period and very‐long period signals associated with hydrothermal processes and magmatic degassing. We model the source mechanism of repetitive long‐period signals in the 0.4–2 s band from a 15‐station broadband network by stacking long‐period events with similar waveforms to improve the signal‐to‐noise ratio. The data are well fitted by a point source located within the summit crater ∼250 m below the crater floor and ∼200 m from the inferred magma conduit. The inferred source includes a volumetric component that can be modeled as resonance of a horizontal steam‐filled crack and a vertical single force component. The long‐period events are thought to be related to the interaction between the magmatic system and a perched hydrothermal system. Repetitive injection of fluid into the horizontal fracture and subsequent sudden discharge when a critical pressure threshold is met provides a non‐destructive source process.