One week ago, scientists at the Alaska Volcano Observatory changed the alert level for Mt. Spurr from yellow to green. According to AVO Scientist-in-Charge Matt Haney, the monitoring data was showing a downward trend in activity around Mt. Spurr for the last several weeks.
Green alert levels indicate that activity is at background levels or trending downward. The volcano had been at yellow levels, or noted unrest with increased earthquakes and the volcano surface changing since mid-October last year. Haney says magma had intruded below the surface.
Mount Spurr never reached an orange alert level, which can mean there is an eruption, though not an explosive one. Haney says these volcanoes spew lava, but do not release ash clouds. Red alert levels are for major eruptions that can release ash clouds thousands of feet into the atmosphere.
Spurr erupted in 1992 three times and produced significant amounts of ash and closed the Anchorage airport for 20 hours. Then, it became active again and stayed at a yellow level from 2004 to 2006, similar to its most recent period of unrest.
Haney says the high point of seismic activity around Mount Spurr’s most recent period of unrest was January through March of this year. It’s been declining since then. Haney says though Spurr is quiet now, the status could change if magma intrudes again. He does note that there are elevated but continued declining levels of carbon dioxide at the crater of the volcano, but so far, sulfur dioxide has not been detected. And he notes this does not impact any of the communities around Mount Spurr.
Haney suggests residents always have a basic supply kit for natural disasters, like those included on the ready.alaska.gov website.
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