![]() ![]() A poorly documented eruption occurred in 1945, also producing a lava dome that was partially destroyed in the 1974 eruption. That eruption produced at least one ash cloud that likely exceeded an altitude of 25,000 ft (7.6 km) above sea level. A steep-sided lava dome, emplaced during the 1974 eruption, occupies the center of the crater. The volcano is a composite structure consisting of an older dissected volcano and a younger parasitic cone with a ~1 mile (1.5 km)-diameter summit crater. It is located 26 miles (43 km) east of the community of Adak. Great Sitkin Volcano is a basaltic andesite volcano that occupies most of the northern half of Great Sitkin Island, a member of the Andreanof Islands group in the central Aleutian Islands. Great Sitkin is monitored by local seismic and infrasound sensors, satellite data, web cameras, and regional infrasound and lightning networks. More than twenty earthquakes were located beneath Great Sitkin over the past week, but the earthquakes were all small with magnitudes lower than 1. Weakly elevated surface temperatures and a steam plume were observed in satellite data this week in mostly cloudy viewing conditions. Multiple satellite radar images this week showed that the lava continues to slowly move to the east into the intracrater glacier. Lava continued to erupt slowly at Great Sitkin over the past week, adding to a thick lava flow confined to the summit crater.
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