Wednesday, February 15, 2012

Eruption at El Hierro Slows, But Quakes Increase

The harmonic tremor at El Hierro has been extremely low for the last couple of days, but the volcano is still weakly erupting magma, and mostly degassing. However there were a record of over 20 earthquakes yesterday and into today, with the quakes becoming shallower and shallower, possibly a precursor for another vent in the SW part of the island off the coast. The magma chamber is not done yet with El Hierro.

The harmonic tremor is at a low point due to probable vent collapse, and re pressurization of the chamber (think of it like putting your thumb, or a cork, in a running garden hose, but on a much more massive scale). The pressure will build up and the eruption of the current vent will either resume, or the magma will find another route to the surface. It is anyone's guess where and when, but it seems likely that the new vent if it does pop up will be to the West of the current cone (Bob).

The current tremor and analysis from El Hierro volcanologists confirm this, and now the island waits to see the next phase of this historic event. More than likely, this will result in another submarine cone building event. If another cone/fissure does erupt in another location, you can be pretty sure that the first cone (Bob) will stop erupting as magma diverts to an easier route. This may be already taking place, with harmonic tremor so low, and quakes so numerous and shallow, it could very well be that "Bob" is dead.

This would actually end up being a good thing for the village of La Restinga as their main port and tourist spots have remained closed out of an abundance of caution, and all sea faring routes have been cut off. This has hit the economy hard. An eruption to the West of "Bob" would be of minimal consequence to business, especially if "Bob" is confirmed to be done erupting and the government re-opens boat traffic to La Restinga (not to mention the hotels and cafe's).

No comments:

Post a Comment

Comments are moderated. See the comment policy for details.