The 1950 eruption of Santorini volcano (Nea Kameni)
The 1950, or Liatsikas, eruption was a weak eruption (but still stronger than most phases during the previous eruptions in 1925-28 and 1939-41) and produced a small flat lava dome, following a series of weak to moderate phreatic explosions that opened 2 vents in the location of fissures that had developed during the previous eruptions.
The blocky lava dome (Liatsikas lavas) from the 1950 eruption on Nea Kameni, the (so-far) youngest rocks of Greece.
It followed 8 1/2 years after the previous eruption that ended with the formation of the Niki lava dome in 1941, and occurred very close to it.
Georgalas suggests that the 1950 eruption represents the effusion of a rest amount of magma from the same chamber than the 1939-41 eruption, which was prevented from erupting then, because the lavas had cooled too quickly and had temporarily blocked the vents, until 8 and a half year later, gas pressure was large enough to un-block the way. When this happened, the same fractures were used as pathways.
Precursors of the eruptionEarthquakes were noted by inhabitants of the island on 15 December 1949, and in the days preceding and during the eruption on 10, 11, 13 and 16 January 1950.
At that time, there was no seismic monitoring, so only quakes of magnitude significantly above 3 have been recorded, but there could have been many more small ones.
The eruption starts: 10 Jan 1950The first explosion took place at 01h00 on 10 January 1950, accompanied by weak noises and a felt quake. 11 other weak explosions could be observed until 8h35. The activity originated from the eastern flank of the Georgios cone, about 175 m away from its summit.
Until noon, 7 more weak explosions and one stronger one were noted, the latter produced a loud nois and a dense column of sandy ash. Between 13h50 until 16h50, 6 weak explosions took place with white-gray clouds, and 3 larger explosions that erupted dark gray clouds of ash.
Georgalas, who reports the events during this eruption, notes that the normally weak fumaroles in other parts of Nea Kameni suddenly were much more intense since the eruption started.
Residents in Fira noted lightnings and small flames at night in the ash cloud erupted from the eruption site.
Second day of the eruption (11 Jan 1950)Explosions increased and occurred all day long. Most of the produced mainly steam clouds, the more violent ones gray ash plumes, some lasting up to 2 minutes. Lightnings were again visible at night.
Between 11h00 and 15h00, Georgalas counted 17 eruptions.
At night, the eruption intensified, and amoderate quake (probably 3-4 magnitude) was felt by all inhabitants. 5 minutes later, a violent explosion occurred.