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1979
Feb 06: 500 m plume height Explosions, incandescence
14-15: 500 m plume height Explosions, ashfall
19: 500 m plume height One explosion
22: -- One explosion
Mar 11-13: 500 m plume height Four explosions
Jun 05: -- Incandescent column, explosions
Jul 20: 500 m plume height Seven explosions, ash emissions
21: 200 m plume height Ash emissions
Sep 05-06: 2000 m plume height Frequent, strong explosions, incandescent columns,
ashfall to sea
07: 1000 m plume height Ash emissions
08: 800 m plume height Ash emissions
09: 2000 m plume height Frequent explosions
12: 1000 m plume height Ten explosions
Dec 10: 1500 m plume height Explosions, incandescent blocks, reflected glow
11: -- Ash emissions
12: -- "Flames" in crater
18: 300 m plume height Three explosions

1980:
Feb 05-06: 1500 m plume height About 10 explosions, incandescent column
Mar 21-22: 1000 m plume height Many explosions
Apr 25-26: 1500 m plume height Explosions: ashfall on inhabited areas
May 13: -- Three explosions
18: 500 m plume height Six explosions; persistent ash ejection
Jun 04-05: 500 m plume height More than 25 explosions
Jul 16-19: -- Many explosions
Aug 03-08: 1500 m plume height Several tens of explosions; incandescent column
21-23: 1000 m plume height More than 20 explosions; incandescent column
Sep 08-09: 1000 m plume height More than 1000 explosions
20: -- Three explosions
24-27: 2000 m plume height More than 1000 explosions
Oct 25-27: 500 m plume height Persistent ash ejection
Nov 08-10: 1500 m plume height More than 1000 explosions
29: 500 m plume height Persistent ash ejection
Dec 13: -- Explosions