Krakatau volcano news & eruption updates:
Krakatau volcano (Sunda Strait, Indonesia): field report 19-23 Nov - strombolian activity, ash emissions and lava flow
Friday Nov 23, 2018 13:01 PM | BY: T
New lava flow on the southern flank of Anak Krakatau on 19 Nov evening (image: Tom Pfeiffer / VolcanoDiscovery)
Sea entry of the 17-18 Nov lava flow (image: Tom Pfeiffer / VolcanoDiscovery)
During our latest visit to the volcano from 19-23 Nov, we observed intense strombolian to vulcanian activity with strong ash emissions as well as an active lava flow. As of now, the volcano has calmed down to very low levels of activity during the past two days, after an intense phase during 17-19 November.
Strombolian activity at the summit vent on 19 Nov (image: Tom Pfeiffer / VolcanoDiscovery)
Accompanied by pulsating strombolian activity at the summit vent of Anak Krakatau, a new lava flow started to descend on the southern slope of the summit cone probably on 17 November evening, and reached the sea by 18 November evening (or earlier) when it was visible on the webcam. Probably, the peak of this activity occurred on that evening (18 Nov) including pulsating lava fountaining and high effusion rate. The sea entry was along a delta of about 150 m width.
At the time of our arrival at around 13:00 on 19 Nov, the lava flow was no longer alimented significantly, but the lower part continued to push the lava front against the ocean, producing a strong steam plume with occasional small littoral explosions.
At the summit, strombolian activity of small to strong size, with ejections ranging from tens of meters to few hundreds of meters height, continued at short intervals (20 seconds to few minutes at most). This activity was also accompanied by intense ash venting, and quite noisy, with occasional strong lava bubble burst sounds.
In the evening, two short-lived surges of activity produced two new lava flows that traveled over the previous one on the steeper part of the slope, but only lasted about an hour each. The second and larger of the two reached the base of the cone and stalled there in a front about 50 meters wide.
During the following days, activity gradually decreased: It remained intense during 20 Nov, with still very frequent strombolian activity and ash emissions of varying intensity, but individual explosions now occurred at longer intervals (minutes to tens of minutes), and some much stronger, vulcanian-style explosions began to occur (similar to what we had observed in mid October), sending blocks to heights of over 1000 m and occasionally into the sea. The steam plume of the ocean entry described earlier had ceased.
On 21 Nov, the intervals between explosions and ash emissions had become significantly longer (up to 1 hour) and the ratio between incandescent to already dark material ejected had decreased dramatically - on photographs, the brightness of individual eruptions had decreased by two orders of magnitude, suggesting that the magma column by now had dropped significantly.
This trend continued during 22-23 Nov although some explosions that occurred then were particularly violent and sent bombs into the forest of Anak Krakatau.
Activity almost ceased last evening (22 Nov), with only very few and small ash emissions occurring from time to time.
Wednesday, Nov 21, 2018
Tuesday, Nov 20, 2018
Monday, Nov 19, 2018
Krakatau volcano (Sunda Strait, Indonesia): increasing activity, possibly paroxysm with lava fountains and lava flow
Monday, Nov 19, 2018
The activity of the volcano has increased yesterday. Available data suggest it might have had a so-called paroxysm, a temporary strong peak of activity including possibly lava fountaining and lava flow emission. ... [more]