Low-level eruption of lava and increased seismic activity at Pavlof volcano
Alaska Volcano Observatory (AVO) reported increased seismic activity at Pavlof volcano and presence of intense elevated surface temperatures on the morning of May 13, 2013. An intense thermal anomaly at the summit was observed in latest satellite imagery. AVO reports that similar patterns of seismicity and elevated surface temperatures have previously signaled the onset of eruptive activity at Pavlof.
The agency states that although not yet visually confirmed, a low-level eruption of lava has likely begun from a summit vent, but there have been no significant ash clouds detected so far.
Satellite images and pilot reports revealed that a spatter-fed lava flow has advanced about a half a kilometer down the north flank of the volcano on May 14, 2013. AVO raised Volcano Alert Level from Advisory to Watch and Aviation Color Code from Yellow to Orange.
AVHRR satellite image from May 13, 2013 at 16:23 UTC shows thermal anomaly at Pavlof volcano (white pixels inside pink circle). This thermal anomaly is likely the result of new lava at Pavlof. (Credit: AVO/AVHRR)
Weather clouds currently obscure the view of the volcano from Cold Bay, the nearest community. Pavlof is monitored by a 9-station seismic network of which 5 stations are currently operating.
Brandon Wilson, PenAir pilot, took this image of Pavlof steaming, with fresh lava flow on its north flank. May 13, 2013. Brandon was at about 10,500 feet, westbound from Sand Point to Cold Bay. (Image courtesy of Brandon Wilson)
The most active volcano of the Aleutian arc, Pavlof is a 2519-m-high Holocene stratovolcano that was constructed along a line of vents extending NE from the Emmons Lake caldera. Pavlof and its twin volcano to the NE, 2142-m-high Pavlof Sister, form a dramatic pair of symmetrical, glacier-covered stratovolcanoes that tower above Pavlof and Volcano bays. A third cone, Little Pavlof, is a smaller volcano on the SW flank of Pavlof volcano, near the rim of Emmons Lake caldera.
Pavlof volcano and eruption plume on evening of August 30, 2007. View is to the S, out of the right side of a PenAir Metro Airline plane en route to Anchorage from Cold Bay; plume height was approximately 5.2-5.5 km. (Courtesy of Chris Waythomas and AVO/USGS)
Unlike Pavlof Sister, Pavlof has been frequently active in historical time, typically producing strombolian to vulcanian explosive eruptions from the summit vents and occasional lava flows. The active vents lie near the summit on the north and east sides. The largest historical eruption of Pavlof took place in 1911, at the end of a 5-year-long eruptive episode. During this eruption a fissure opened on the northern flank of the volcano, ejecting large blocks and issuing lava flows. (Global Volcanism Program)
Index map showing location of Pavlof volcano and other Alaska Peninsula volcanoes. (Credit: Snedigar, Schaefer/Image courtesy of the AVO/ADGGS)
Featured image: Pavlof steaming, with fresh lava flow on its north flank on May 13, 2013. Pilot was at about 10,500 feet, westbound from Sand Point to Cold Bay. (Image courtesy of Brandon Wilson)