Thursday, January 19, 2012

El Hierro Volcano Still Erupting

The eruption at El Hierro continues at a steady pace. Harmonic tremor has fluctuated during the past few weeks, with tremor picking up in the last couple of days following a supposed vent collapse (possibly two). Last night, viewers of the webcams reported seeing flaming lava balloons on the surface of the jacuzzi area, with sporadic increases and decreases in jacuzzi intensity.

As of this writing, tremor is picking up, which has become somewhat typical following vent collapse. This is a result of re-pressurization of the vent magma chamber, which will likely result in further underwater cone building and subsequent collapses, until the volcano either breaks the surface and enters a surtseyan eruptive phase, or the eruption ceases altogether.

El Hierro volcano has vexed bloggers, enthusiasts, and scientists alike, with frequent stops and starts to the eruption action. Some bloggers like John Frimann (Iceland Volcano And Earthquake Blog) and Earthquake-report.com (who currently has the best equipped coverage of the area, sans opinions) have previously reported the eruption to be over, which is obviously not the case.

As is sometimes a fact with long dormant volcanoes, eruptions can be long lived, or short in duration. The eruption at El Hierro was preceded my many thousands of small earthquakes, which resulted in a good picture of the girth of the magma chamber, which it turns out, is quite large. This is one of the least studied volcanoes in the Canary Islands, if not THE least studied. So most of the info about El Hierro is quite new.

The magma chamber is large, and has clearly made a channel to a massive magma source, probably deeper than scientists are currently able to measure without the aid of a massive seismic network, or the newly minted muon scanning technology. Judging from the earthquakes alone, in conjunction with depth, magnitude, location, etc, it seems this eruption probably has plenty of pressurized magma to feed activity for months to years.

In my opinion, this will be a very sustained and long eruption, possibly resulting in the creation of a new island. If the volcano ever does break the surface of the water and enter a land-building phase like the new island in Yemen (in the Jebel Zubair chain), the eruption will likely speed up with no water pressure to hold it back. A lack of water at the vents surface would allow the eruption to "blow its load" so-to-speak, resulting in probably a quicker release of magmatic gas pressure. This of course is only my theory.

In any case, the eruption continues unabated, and is beginning to develop a pattern of vigorous cone growth followed by periodic collapses and a subsequent increase in tremor and pressure. The lava balloons on the surface seem to indicate a very even flow of lava to the vent area, very consistent.

I will post more updates if anything interesting occurs. 

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