Fig. 3.From: Short-term spatial change in a volcanic tremor source during the 2011 Kirishima eruptionMUSIC spectrum analysis applied to the explosion on 1 February, 2011. Top: seismograms of the vertical component observed by the array. Center: time-slowness section of the spectrum from N65°W used to obtain the reference slowness of P-, and surface, waves (0.42 and 1.0 s/km, respectively). Bottom: particle motion analysis applied to the broadband seismogram (KU.KRSY): (a) three-component seismogram; (b) ratios of e1 to etot, and e1 × e2 to etot, where e1 and e2 are maximum and moderate eigenvalues. etot is defined in the text; (c) azimuths of the eigenvectors; (d) right and left particle motion are extracted from P-, and surface, wave arrivals in the green and orange time windows, respectively. Both orbits indicate the ground velocity in a radial direction from the crater.Back to article page