Wednesday, December 7, 2011

El Hierro Eruption Resumes Activity

On Dec. 5th, eruptive activity was strong at El Hierro in the Canary Islands, Spain. Video from the scene showed strong 'jacuzzi' action and a large green stain in the ocean. The helicopter flyover is probably the best video to look at on the mentioned link, which gets quite close to the surface for a really spectacular view. Video for today however is a bit tough to come by (if any readers feel they'd like to post some more current video links, I'd be much obliged).

While tremor has died down, and resumed, and died down again on the island, the eruptive activity has also stopped and started again many times over the last month. I believe this volcano will eventually burst through the surface of the ocean as it appears thus far to be a long term eruption. Indication are that magma is still on the move underneath the island and as indicated by surface observations, this eruption is anything but winding down.

If indeed the volcano does break the water surface, you can be assured that its entrance will be much like the eruption of Surtsey in Iceland in the 1960's. Once the volcano does break the surface, it will be in it's "Surtseyan Phase", meaning it is starting to build an offshore island, and will likely be accompanied by explosive activity, and probably some ash clouds. This phase lasts until (typically) the cone closes off the erupting lava from the sea water, at which point, the eruption can change to other eruptive types. It could be that smooth pahoehoe lavas would be erupted, or it could be a more explosive, rhyolitic eruption.

From the chemical analysis of the lavas thus far, all indications are that it will likely be a rhyolitic eruption. Since submersible ROV's have not been able to directly observe the underwater eruption, they have no direct video evidence of the characteristics of the lava on the sea floor (ie: whether it is blocky, chunky lava, or smoother pahoehoe pillow lava). The samples taken from the ocean surface that have floated up are high in gas content, and rhyolite, meaning that once the volcano pierces the ocean surface, it may very well be an explosive, and potentially dangerous eruption for the residents of El Hierro, but at this time, that's all speculation, and not based on any scientific fact.

Keep your eyes peeled on the El Hierro webcams, as you might be fortunate enough to see the birth of a new island via live streaming! If the eruption continues on at the pace it is, it's only a matter of time before you can see a brand spanking new island be born. The only downside to viewing the webcams from the West Coast in the USA is that it's usually night time over in the Canary Islands by 10am here... So I've had a few sleepless nights gazing at the eruption cams, and some very early mornings.... but it's well worth it.

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