Photos by Dr. Edward Kohut, all rights reserved, used by permission, 2009
Many times people think that volcanic eruptions affect the economy through the destruction inflicted upon the landscape during an eruption: lahars and pyroclastic flows destroying bridges and homes, ash ruining crops and water, lava flows overunning communities. However, in Hawai’i, a new effect of volcanism has been seen in the agriculture of the state. The volcanic fog – or “vog” as its called – has been causing major problems with farms on the Big Island of Hawai’i. Since the new activity at Halemaumau (see above) began last year, Kilaeua has been spewing much larger volumes (2-4 times more) of volcanic gases such as sulfur dioxide, carbon dioxide, water and carbon monoxide than in previous years. These gases form a brown fog that is caustic to most animals and plants. The sulfur dioxide, in particular, has caused many crops to fail thanks to the production of sulfuric acid with the sulfur dioxide interacts with water – think of it as a very concentrated version of “acid rain” that is seen in the eastern United States.
The solution to this would either be to build “vog-proof” air-filtering greenhouses or planting a limited set of plants that seem to withstand the effects of the vog. Alternately, one can hope that the gas emissions from Kilaeau will return to lower levels, allowing for the plants to survive. In any of these cases, the growers on the island face a large financial hardship in order to keep their businesses alive in the face of the volcano. This passive destruction of plants by Kilaeua shows how even when a volcano seems to be benign, it can inflict millions of dollars of damage on the local economy.
A week ago, if you asked around, I’m sure most people would have thought Redoubt would have erupted by now considering all the seismicity and melting that was seen at the end of last week. However, volcanology is not an exact science, and here we are continuing to watch Redoubt tease us with signs of pending activity. New holes have appeared in the snow that caps the volcano, the seismicity continues and the volcano is still spewing sulfur dioxide, carbon dioxide and hydrogen sulfide – all signs that magma is intruding the volcanic edifice. However, as on this morning (2/5/2009), the volcano has yet to erupt.
Some news from earlier in the week is that the US Air Force has moved many of its aircraft from the area of Redoubt to Washington state, apparently not wanting to play the waiting game like it did during the 1991 eruption of Pinatubo near Clark Air Base. Also, an eruption of Redoubt might also have a larger effect on air cargo rather than air passenger traffic, with one of the largest air cargo hubs located in Anchorage.
UPDATE 9:20 AM 2/5/2009: Read into it as you will, but Redoubt’s activity is in “slight decline” according to AVO.
I was chatting with a fellow from AVO and he called the simultaneous eruptions of Kasatochi, Cleveland and Okmok a “once in a millennia” event. So, enjoy it!
He also mentioned that the Kasatochi eruption released the most sulfur dioxide into the atmosphere since the 1991 Pinatubo eruption … but we had an idea of that already.
And who knew that there has been uplift at Uturuncu in Bolivia? I sure didn’t, but Steve Sparks does.
More to come later this week when I can go to all the Chaiten posters.
Just to keep everyone on their toes, Soufriere Hills on Montserrat in the West Indies erupted today. The eruption produced a number of explosions and a pyroclastic flow that originated from the west side of the lava dome at the summit of the volcano. However, the most interesting bit comes from the Montserrat Volcano Observatory (MVO) report I received this morning:
“The explosion happened without any warning. There was no precursory seismic activity.”
Sounds like it could have been a dome collapse caused by a rapid release of gas/steam? The explosion apparently threw blocks as far as a kilometer from the dome and incandescent (i.e., hot) material end up on Gages Mountain slopes. The pyroclastic flow itself made it all the way to the sea via Plymouth (the former capitol) and building were set ablaze by the flow in the abandoned city. The ash column from the eruption is also producing lightning.
Sounds like we’re beginning to get a better idea of what is erupting in Ethiopia. Ghezahegn Yirgu, a geologist at Addis Ababa University, reports that Dalla Filla Dalaffilla Volcano is the source of the eruption. Again, the eruption is being characterized as “lava flows” rather than an explosive eruption, which may be surprising considering the amount of volcanic gases being released (see Boris Bechnke’s highly useful comment). However, some mostly effusive eruptions have released a lot of volcanic gases in the past – see Laki, Iceland in 1783 – so a preponderance of flows at Dalla Filla Dalaffilla would not be shocking.
Now, there is surprisingly little information I can find about Dalla Filla – in fact, it doesn’t even appear in the GVP database or, for that matter, almost anywhere on the internet. The volcano is located, according to the article linked above, about 20 km north of Erta Ale, so it is in a region of active East African Rift volcanism. The map above (from the USGS) shows all the volcanoes in the area that have known eruptions since 1800, so unless Dalla Filla is being confused with Dallol, it might be the first eruption of the volcano in quite some time. I’ll update once I can find more information on Dalla Filla (and feel free to comment here if you know more than I).
REVISED (11/6/08): Apparently, the volcano in question is Dalaffilla, which shows up in the GVP website (Thanks Ole and Ron). There isn’t much information on Dalaffilla, except that, surprisingly, it appears to be a silicic volcano. The reports I’ve read so far seem to indicate that lava flows have spread out over a large area, which would suggest a low viscosity (i.e., basaltic) lava. Thanks to the Eruptions readers who dug out some great information.
Sorry about the lack of update. Having no internet while moving will do that! I did see an email this morning that had some interesting information about the amount of sulfur dioxide emitted by Kasatochi (Alaska) during the current eruption (thanks to Simon Carn, UMBC):
“The August 7-8 eruption of Kasatochi volcano (Aleutian Islands)produced a very large stratospheric SO2 cloud – possibly the largest since the August 1991 eruption of Hudson (Chile). Preliminary SO2 mass calculations using Ozone Monitoring Instrument (OMI) data suggest a total SO2 burden of ~1.5 Tg. This figure will be revised in the coming weeks but is more likely to go up than down. The SO2 cloud has drifted over a large area of North America and is now (August 14) reaching Europe.“
It seems like Kasatochi has released quite a large flux of sulfur dioxide into the atmosphere. What effect this might have on climate is hard to tell, typically large SO2 fluxes will lower global temperature (or at least hemispheric temperature) by a fraction of a degree annually – which can actually still have a perceivable effect on weather. For those of you interested in where all the SO2 is in the atmosphere, try out this site run by NOAA that provides maps and predictions for SO2 movement.