After several months of relative quiet at Bezymianny Volcano, an increase in earthquakes prompted the Kamchatka Volcanic Emergency Response Team (KVERT) to raise the aviation color code from yellow (signs of elevated unrest) to orange (heightened or escalating unrest) on February 19, 2012. Less than two weeks later, on March 2, KVERT increased the alert to the highest level (red): “eruption is imminent, with significant emission of volcanic ash into the atmosphere likely.”
In the first week of March the daily number of seismic events roughly doubled, and KVERT scientists recorded volcanic tremor (continuous, rhythmic ground shaking associated with the movement of magma) on March 2nd. At the same time, satellites measured an increase in temperature of the volcano’s growing lava dome.
The Advanced Land Imager (ALI) on the Earth Observing-1 (EO-1) satellite collected this true-color image of Bezymianny on March 5, 2012. A plume of steam and other volcanic gases escapes from the lava dome, the same region with elevated surface temperatures. Most of the landscape is covered in late-winter snow, but the southern face of the volcano has a fresh layer of brown ash. The lava dome itself, currently the summit of the volcano, rises above a crater rim that formed during an eruption in 1956.
NASA image by Jesse Allen and Robert Simmon, using ALI data from the EO-1 team. Caption by Robert Simmon.
An increase in earthquakes under Bezymianny Volcano signaled an impending explosive eruption.