In the Aleutian Range island arc lies the massive Veniaminof volcano (56°11’52” N 159°23’35” W), a 2507 m (8225 ft) stratovolcano. It is one of the most prominent in Alaska, neighbour to the closely monitored Aniakchak and Pavlof volcanoes.
Historical activity arises from the two prominent intracaldera cones. The currently inactive larger one barely rises above the glacier surface. Several post-caldera cinder and scoria cones are aligned on a NW trending line from the Bering Sea coast down the Pacific slope.
Seismicity of the past 10 years show a clear vertical trend of earthquakes up from the wrinkled Wadati-Benioff zone of the Pacific Oceanic plate, feeding the subduction zone related volcano.
The USGS Alaska Volcano Observatory (AVO) maintains one of the best public volcano monitoring websites on the internet in my opinion with all information one could possibly wish for clearly laid out. 17 eruptions have been recorded in historic times since 1830 (AVO eruption time-line of Veniaminof) with some increasing frequency in recent years. The GVP denotes several periods since September 2002 of on-and off activity with low-frequency tremor as first sign of volcanic unrest, steam and minor ash exhalations from the historically active intra-caldera cinder cone. With the webcam installed in Perryville (32 km SSE, population 113) in 2004 many low-level eruptions above the crater rim could be monitored on clear days in the following years. In January 2005 a long thin ash cloud stretching as far as 55 km was observed. A heat anomaly caused by low level strombolian activity at the summit lead to orange alert throughout February 2005. Low-level seismic activity and occasional minor ash emissions continued until 2008.
Last year in June volcanic tremor set in again, indicating lava effusion and orange alert was declared again. In the following weeks small explosions above the crater rim were observed, at least four steam and ash plumes up to 4.6 km a.s.l. until August 2013. Activity markedly increased on August 20 when loud explosions coming from Veniaminof were heard in Perryville, coming to a climax on August 30 with intense seismicity, lava fountains and ash clouds rising to over 6 km a.s.l. (see video). After some temporary decrease in seismic and volcanic activity Mt. Veniaminof flared up again on October 6. Timelapse of eruption on 30 Aug 2013:
Veniaminof seems to have taken a rest since last October, although the alert level is still at yellow with seismicity remaining slightly above background.
In the meantime, a few hundred kilometers to the SW, Shishaldin came to live again after some unrest in 2009, and the aviation color code was raised to yellow on 30 Jan 2014 due to elevated surface temperature and increased steam emission. Shishaldin is less than 10000 years old and and the beautiful symmetrical cone reaches highest amongst all volcanoes in the Aleutean island arc (2857 m).