Krakatau volcano (Indonesia): vulcanian explosions - field report 13-19 Oct 2018
sam., 20 oct. 2018, 10:3510:35 AM | AUTEUR : T
Vulcanian eruption at Krakatau on the evening of 13 Oct 2018 (image: Tom Pfeiffer / VolcanoDiscovery)
Vulcanian explosion during the morning of 17 Oct 2018 (image: Tom Pfeiffer / VolcanoDiscovery)
A small group of VolcanoDiscovery stayed on the island group during a Volcano Special tour from 13-19 Oct: the volcano's activity during this time fluctuated between phases of mild to strong ash venting along with occasional strombolian activity, as well as intermittent powerful vulcanian-type explosions.
Mild strombolian activity in the evening of 14 Oct 2018 (Tom Pfeiffer / VolcanoDiscovery)
The latter often occurred in series lasting 4 to approx 20 hours and at intervals ranging from 20 minutes to 3 hours. They typically generated loud detonation sounds, ejected bombs to heights up to 600-800 m or more, sometimes reaching the shores of Anak Krakatau and even the sea. Ash plumes rose approx. 2-3 km, and often showed frequent small lightnings.
No lava flows were active during our stay at the volcano, but there have been spots with constant glow along the line of the mid-September lava flow on the southern slope.
Interestingly, the recent (and still ongoing) eruptive phase has constructed a new cone that filled the old summit crater almost completely, except the eastern rim, which remains as a break in slope of the new cone. We estimate that the height of Anak Krakatau increased by approx. 25-30 percent as a result, now probably about 450 m tall.
The vulcanian explosions were particularly intense during the night 13-14 Oct, the evening of 15 Oct and the night 16-17 Oct until the next morning. In the afternoon of 17 Oct, a particularly violent explosion occurred that excavated a pit crater beneath the southern lid of the crater, at the same location the September lava flow had overspilled from the crater. By 19 Oct, this new pit had merged with the main crater, enlarging it.
Link: Photos and video from the expedition
mer., 17 oct. 2018, 22:00