Busy week, time to catch up a bit:

Iceland

Right now, the news out of Iceland is much the same as its been for the last week: lava flows issuing from some of the Holuhraun Lava Field fissures, possible melting under the ice cap especially in the Barðarbunga caldera and earthquakes continuing to rumble. I personally can’t get enough of the aerial views of the eruption, so be sure to check out the footage shot by Simon Redfern (Cambridge University) that captures some amazing lava fountains and flows from the eruption (see above). The lava flows have reached the Jökulsá á Fjöllum River, but little explosive interactions have been seen. This is likely because there is just too much lava for the volume of water in the river, so intense of explosions, you just get quenching of the lava (and a lot of steam). The NASA Earth Observatory released a stunning Landsat 8 image of the lava flow field and fissure (see below), showing the long tongue of lava that reaches down to the riverbed. The channelized flows near the fissures are evident in the image, but as it travels further and onto flatter ground, the lava fans out into the platy pahoehoe (and even a’a) at the toe of the flow.

False color Landsat 8 image showing the lava flows from Holuhraun fissures. The infrared is emphasized to show the extent of the lava flows. NASA Earth Observatory.

The biggest hazard that Iceland has faced from the eruption is sulfur dioxide. The plume itself now stretches across the North Atlantic and reports of sulfur odor have been noted in Scotland and Norway. However, it is eastern Iceland that is bearing the brunt, with sulfur dioxide concentrations of ~2600 μg/m³ (roughly equivalent to 1 ppm). Using the sulfur dioxide hazard warnings used in Hawaii, this would be “red”, meaning everyone will start to feel the effects of the sulfur dioxide and outdoor activities should be curtailed.

There is rising concern that the focus of the eruption could move to within the Barðarbunga caldera as subsidence of the caldera floor is continuing. This could cause new cracks to open in the crust and offer a path for the lava that is currently erupting at Holuhraun to erupt from within the caldera. The major hazard of this scenario would be a very large jökulhlaup (glacial outburst flood) formed from the rapid meeting of the hundreds of meters of ice within the caldera bowl along with a lesser threat of explosive basalt volcanism. Barðarbunga has a history of erupting basaltic tephra (ash and debris), so it isn’t out of the question that the mix of basalt magma and meltwater could cause a much more explosive manifestation of the eruption. However, the likeliest scenarios, at least in the opinion of the Icelandic Meteorological Office volcanologists, are: (1) the eruption could subside and end or (2) subsidence in the Barðarbunga caldera will cause the Holuhraun eruption to end with no eruption from the caldera itself.

Hawaii

The current lava flows on the flanks of Kilauea. In the middle is a kipuka, a piece of forest isolated by the advancing lava flows. USGS/HVO.

The lava flows that are threatening homes on the slopes of Kilauea are continuing. At the current rate of movement (~400 m/day), the lava flows could reach the edge of the Kaohe Homesteads by tomorrow sometime. Discussions are ongoing about what the potential fallout from these lava flows might be, especially because if the lava flows continue, they could reach a major road to Pahoa within 2 weeks. However, many realize that this is the hazard of living on the slopes of an actively erupting volcano. A recent shot of the lava flows (from September 10), show how the lava has burned its way through the forest and in the process, created a kipuka – an isolated “island” of forest surrounded by new lava flows (see above).

Viral Videos

There have been a couple videos making the rounds on the interwebs this week. One is super cool and it captures the explosive shockwave from an eruption from Tavurvur in the Rabaul Caldera. This eruption was tiny, but you can see the force of the strombolian explosion UPDATE: on second thought, it is more likely to be a vulcanian explosion, driven by overpressure of a solid lava plug in the conduit of the volcano. It is reminiscent of the explosion that was captured by the webcams at Popocatepetl last year. The other video has someone climbing into the Ambrym lava lake in Vanuatu with a GoPro camera. Now, sure the footage is great, but this is roughly the volcanic equivalent of the guy at the circus who sticks his head in the lion’s mouth. My concern is footage like this might convince people that its “safe” to do stuff like this (see people standing over ocean entries in Hawaii).

Video: Simon Redfern, used by permission.