Veniaminof reported activity

Start:

June 13, 2013 ± 1 Days

Observed

Lava flow:
Steam:
Tephra plume:
"Fire", "Glowing", or incandescence:

Description: On June 8, 2013, citing gradually increasing seismic tremor, AVO increased the Aviation Color Code to Yellow and the Volcano Alert Level to Advisory.

Over the next several days, seismic tremor continued and clear webcam images from the FAA cam in Perryville showed a persistent steam plume rising over the central cone within the caldera.

On June 13, 2013, AVO increased the Aviation Color Code to Orange and the Volcano Alert Level to Advisory, noting that elevated surface temperatures observed in satellite data from that morning indicated an eruption of low-level effusive activity and small explosions was likely underway. Seismic tremor continued and webcam views were cloudy. Late on the evening of June 13, at 11:23 pm AKDT (07:23 UTC on June 14), a pilot observed an ash plume up to about 12,000 ft above sea level and a lava flow issuing from the intracaldera cinder cone. Residents in Perryville and Port Moller also reported observing the ash emissions at about 11:30 pm AKDT (07:30 UTC on June 14). By June 18, the lava flow extended about 1600 ft (500 m) down the slope of the cone and onto the adjacent snow and ice field. On June 19, residents in Sandy River reported seeing ash bursts from the volcano rising to 10,000-15,000 ASL and blowing to the northeast.

Over the next several weeks, nearly continuous volcanic tremor, elevated surface temperatures indicative of lava emission, and small ash and steam plumes (less than 15,000 ft) persisted at Veniaminof. By July 5, the lava flow extended a few thousand feet south of the intracaldera cone and had multiple lobes. The eruption continued to be characterized by low-level seismic tremor, elevated surface temperatures as seen in satellite imagery, and effusion of lava and emission of minor amounts of ash and steam. Incandescence was occassionally visible in images from the FAA webcam at Perryville. This behavior persisted throughout July, 2013.

In late July and early August, seismic activity decreased in amplitude, although elevated surface temperatures, and emission of lava and ash continued. By August 9, montitoring data suggested a pause in eruptive activity - elevated surface tempertures, consistent with cooling lava flows, were detected in satellite imagery and seismic activity was greatly reduced, although still above background.

On Sunday, August 11, the seismic tremor level increased, and very high surface temperatures were again observed, consistent with renewed lava extrusion. On Monday, August 12, the FAA webcam in Perryville recorded several westerly-directed intermittent steam-and-ash plumes which rose to about 12,000 ft. Over the following week, seismicity again declined, and changed from nearly continuous tremor to more discrete earthquake activity and short bursts of tremor. Low-level steam-and-ash plumes continued to be visible in Perryville webcam images. AVO also received several reports of rumbling noises and explosions (heard and felt) from residents of Perryville.

From August 30 through September 2, increased seismicity, continuous tremor, lava fountaining, and ash emissions of 15,000-20,000 ft occurred at Veniaminof, marking some of the strongest eruptive activity within the 2013 eruption.

Over the next two weeks, the lava effusion and small, intermittent steam and ash plumes continued, but seismic tremor declined in amplitude. On September 20, 2013, citing a decline in seismic activity and lack of evidence of ongoing lava production for the previous week, AVO lowered the aviation color code to YELLOW and the volcano alert level to ADVISORY.