Possible rockfall event at Augustine, July 7, 2015, 09:25 UTC (1:25 AKDT). The signal at four Augustine seismograph stations are shown with the rockfall first showing at summit stations AUP and AUSS and later at AUJA and AUH on the flank of the volcano. The frequency of the signal from 0-20Hz is shown on the spectrograms on the right, and the waveforms with counts +/- 10K for the short-period stations ( AUP, AUH) and +/- 45-65K for the broadband stations (AUJA, AUSS). The length of the signals in all images are four seconds long.
Data publicly available from http://ds.iris.edu/mda/AV
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