Ash and bombs were observed exploding from the central crater during the 11 July 2017 JCG overflight.
at 2203 on 30 June; the plume extended NE. Over the past weeks, the vent fed several active lava flow fronts that enlarged the land in more or less all directions.
Two similar cases are Bagana and Anak Krakatau, which went from nowhere to perpetually active because a large magma chamber had suddenly become available, in both cases after a massive nearby eruption.
Satellite data from ALOS-2 prepared by JAXA confirmed ongoing activity around the summit vent and on the NE flank, while activity on the W flank had ceased (figure 73).
The fact that is erupting the way it is, is fascinating. The dark steaming lines are active hot flows.Carl If Nishinoshima continues to erupt, and hotter materials from depth arrivesEh this volcano isn’t my cup of tea. A warning of dense black emissions from the eruption was issued by JCG on 20 November, and television footage (Frisk, 2013) showed on 21 November ash and rocks exploding from the crater as steam billowed out of the crater (figure 3).
Then in 1875 Askja erupted in a very large eruption, which started as a larger rifting eruption, between Askja and Krafla. And tectonics (and the switch between WVZ and EVZ) seems to explain it very well.What I want to say is that we might see the last large eruptions of Bardarbunga and Grimsvotn, and from Katla, before all these volcanoes go dormant, together with Hekla, for a few centuries. The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography.Bloomer S H, Stern R J, Smoot N C, 1989. The Philippine plate is rather young and warm, so could melt quite easily.
Dark gray ash plumes were observed at 1.8 km altitude, with ashfall and tephra concentrated around the pyroclastic cone (figure 72).
Blocks were ejected as high as 300 m above the crater rim; red hot blocks were scattered at the base of the cone. Exciting story and hypothesis! Another eruption that began offshore in 2013 completely covered the previous exposed surface and enlarged the island again. The marine exclusion zone was defined as a radius of about 2.6 km from the island.Based on satellite images and a pilot observation, the Tokyo VAAC reported that on 15 February an ash plume from Nishinoshima rose to 3 km (10,000 ft) a.s.l. You can recognize unverified quakes by the light gray outline around the dot. It is a very active area.Note the plateau feature at the top right corner, and the line of cones towards the bottomGiven the rate that Nishinoshima can expell lava, it might not be that incredibly old.I have to wonder if Nishinoshima was to undergo a flank collapse at least as big as Anak Karakatau’s or even bigger, how much of a tsunami risk this could pose to southern and central Japan?Not main land Japan. One thing is though for sure, it would leave measurable signs.This is about when I asked Andrej Flis to plot the available data to see what we would find, and if there would be even a small shard of evidence pointing towards my idea being correct.100km seismic plot indicating plume-root formation at 100km depth. Activity recommenced on 12 July and a 200-m-long lava flow was confirmed on 13 July. Aerial photography of the island that day revealed the extent of the new island compared with the pre-November 2013 landmass (figure 49).On 17 August, JMA cancelled the maritime volcano warning (preventing vessels from approaching within 1.5 km), as a result of the decreased activity.
If these aftershocks are tectonically induced, then the spatial coverage of the aftershocks is indicating the area is becoming/is a jumble of fractured rock…most likely from the crustal stretching and thinning from extensional faulting around the MAR.It’s the question of chicken and egg. The Japan Coast Guard noted that the island had grown to about 2.46 square kilometers and the active cone was about 100 m tall. The extent of the island was about 1,710 m E-W and 1,830 m N-S, creating an area of around 2.29 km2 (figure 28). The collapse would most likely be eastward, where the trench is. If we consider the period between 1700 to 1730, then the whole maxima lasted for about 30 years.