Report on Alaid (Russia) — 17 December-23 December 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 17 December-23 December 2003
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2003. Report on Alaid (Russia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 17 December-23 December 2003. Smithsonian Institution and US Geological Survey.
50.861°N, 155.565°E; summit elev. 2285 m
All times are local (unless otherwise noted)
During 12-19 December, KVERT reduced the Concern Color Code at Alaid from Yellow to Green. Seismicity had been slightly above background levels since 31 October, but KVERT seismologists concluded that it was not related to volcanic activity.
Geologic Background. The highest and northernmost volcano of the Kuril Islands, 2285-m-high Alaid is a symmetrical stratovolcano when viewed from the north, but has a 1.5-km-wide summit crater that is breached widely to the south. Alaid is the northernmost of a chain of volcanoes constructed west of the main Kuril archipelago. Numerous pyroclastic cones dot the lower flanks of this basaltic to basaltic-andesite volcano, particularly on the NW and SE sides, including an offshore cone formed during the 1933-34 eruption. Strong explosive eruptions have occurred from the summit crater beginning in the 18th century. Reports of eruptions in 1770, 1789, 1821, 1829, 1843, 1848, and 1858 were considered incorrect by Gorshkov (1970). Explosive eruptions in 1790 and 1981 were among the largest in the Kuril Islands during historical time.