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Resonances of a volcanic conduit triggered by repetitive injections of an ash‐laden gas
Author(s) -
Molina Indira,
Kumagai Hiroyuki,
Yepes Hugo
Publication year - 2004
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 - 10.1029/2003gl018934
Subject(s) - electrical conduit , volcanic ash , volcano , geology , geochemistry , environmental science , earth science , astrobiology , physics , telecommunications , computer science
A swarm of long‐period (LP) seismic events was recorded in December 2001 before heightened eruptive activity of Tungurahua Volcano, an andesitic stratovolcano in Ecuador. The LP events showed simple decaying harmonic oscillations with frequencies ranging from 2 to 3.5 Hz and quality factors ( Q ) significantly larger than 100. Our spectral analysis of the LP events identified systematic temporal variations in both frequency and Q of the LP events. Assuming a crack resonator at the source of LP events, the temporal variations can be consistently explained by increasing the ash content within the resonator, which may be caused by repetitive injections of an ash‐laden gas into a pre‐existing crack in the conduit as a preparatory process for eruptions.