Infrasound (low frequency sound) signals from an explosion at Semisopochnoi Volcano, recorded on an infrasound array on Adak Island. The array has six elements. By using the difference in sound wave travel time between elements we can determine the direction the sound waves are coming from, in this case from Semisopochnoi about 160 miles to the west. It takes the sound waves from Semisopochnoi approximately 13 minutes to reach the array on Adak.
Image courtesy of the AVO/UAF-GI.
Please cite the photographer and the Alaska Volcano Observatory / University of Alaska Fairbanks, Geophysical Institute when using this image.
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