Abstract
In 1992, a large and dense array of geophones was placed around the
geyser vent of Old Faithful, in the Yellowstone National Park, to
determine the origin of the seismic hydrothermal noise recorded at
the surface of the geyser and to understand its dynamics. Old Faithful
Geyser (OFG) is a small-scale hydrothermal system where a two-phase
flow mixture erupts every 40 to 100 min in a high continuous vertical
jet. Using Matched Field Processing (MFP) techniques on 10-min-long
signal, we localize the source of the seismic pulses recorded at
the surface of the geyser. Several MFP approaches are compared in
this study, the frequency-incoherent and frequency-coherent approach,
as well as the linear Bartlett processing and the non-linear Minimum
Variance Distorsionless Response (MVDR) processing. The different
MFP techniques used give the same source position with better focalization
in the case of the MVDR processing. The retrieved source position
corresponds to the geyser conduit at a depth of 12 m and the localization
is in good agreement with in situ measurements made at Old Faithful
in past studies.
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