Spectrogram of explosive eruption at Shishaldin Volcano, Alaska

Spectrogram of the Eruption
of Shishaldin Volcano on April 19, 1999

Graph showing spectrogram of explosive eruption at Shishaldin Volcano on April 19, 1999

Graph provided by the Alaska Volcano Observatory

Spectrograms for Shishaldin Volcano showing data from 1815 UT to 2135 UT on April 19 (1015 a.m. to 1335 p.m. ADT). A rapid increase in signal level occurs at 1938 UT or 1939 UT, which probably corresponds to the onset of the main eruption. As can be seen from the spectrograms, this signal is very broadband, and saturates (red) at all frequencies.

URL of this document: http://volcanoes.usgs.gov/About/Highlights/Shishaldin/0419_spectrogram_caption.html
Last modified: May 17, 1999

Spectrogram of the Eruptionof Shishaldin Volcano on April 19, 1999

Spectrogram of the Eruption
of Shishaldin Volcano on April 19, 1999