Infrasound is a hugely powerful tool for
precisely locating volcanic ‘radiators’.
Traditional seismology is much less effective for a few
reasons:
1)Volcano
seismic signals are often very emergent, i.e. they grow out of background noise
and are hard to identify onset times.
2)Recorded
volcano seismic signals are very site-specific, i.e., they are not correlated across
a network, or even a dense array of seismometers (unless they are bandpassed
to low frequencies).
3)Seismic
phase velocities are fast…. On the order of several kilometers per
second. This leads to lower
spatial resolution even when events can be well-picked.
Infrasound
radiators can be located using infrasound arrays that act as an antennae and point
to a source (e.g., Ripepe and Machetti, 2002 at Stromboli and Garces et al., 2003
at Kilauea) or they can be used in a network to precisely pinpoint a source (e.g.,
Johnson et al., 2006 at Reventador, Jones et al., in rev. at Erebus, and Johnson,
2005 at Stromboli – featured next).