Tuesday, December 13, 2011

Speculation Grows Regarding 2nd Vent At El Hierro

El Hierro continues to be a very active scene for it's eruption. Today (Dec 13th) sees strong jacuzzi action south of La Restinga, while earthquakes are still down to zero. Earthquakes had migrated North to the bay of El Golfo, and were clustered a mile or so North of the coast. These quakes have ceased, leading some to believe that a possible second vent has finally opened. This is not out of the question, however there is still no proof of this at this time.

The reasoning behind this line of thinking is the fact that when earthquakes ceased South of La Restinga, the vent had entered a stable eruptive pattern. Harmonic tremor continues to be consistent with explosive bursts occurring at regular intervals. However, again we can't be certain that these explosions are exclusive to the La Restinga vent, and could be tied to underwater activity North of El Golfo. But this is still all speculation on the parts of bloggers, and even some scientists.

Due to the depths at El Golfo, it is highly impractical to attempt to monitor the situation with an ROV, or other equipment. It's simply too costly, and difficult at this time. INVOLCAN has mainly monitored the situation near La Restinga, as it's the only vent currently with the potential to affect island residents should it break the surface and enter an ash-producing phase, or island building phase. Gases would be freely released into breathable space, and ash could easily be blown to La Restinga, and the rest of the island. This of course has not occurred yet, but they are monitoring the situation closely.

This morning saw strong activity at the La Restinga vent, with no signs of slowing down. Once lava starts to flow freely from the fissure, it forms a submarine cinder cone (most likely), which concentrates the area where the lava exits the magma chamber. Earlier in the month we saw at least two, possibly three, separate "jacuzzis", which mow appear to have coalesced into one large vent at the summit of the cone. This is normal. Even on land, this is exactly how the cone building phase occurs. We've seen several recent events on land that were similar, like the Nyamuragira eruption that began last month, and the fissure eruption at Fimmvörðuháls near Eyjafjallajökull in Iceland. Both events started with strong fissures, but ended up as cinder cones when the lava started to pile up.

Whether or not a second vent has opened in El Golfo is anyone's guess. We likely will not know until INVOLCAN allows underwater teams to survey the area after the situation has calmed down, or the eruption ceases. INVOLCAN is gathering as much info as possible about this eruption, as El Hierro has traditionally been the LEAST studied volcano of the Canary Islands, with more attention being paid to La Palma and Tenerife historically. Even though El Hierro is the youngest of the Canary Islands, it seems nobody ever anticipated an eruption. The last eruption (which is unconfirmed by Smithsonian GVP, but seems to be local fact in El Hierro) was supposedly in 1793, so two centuries and some change is a long time to sit and watch a dormant volcano.

The Island of La Palma is of interest to the media, and doomsayers, who every once in a while like to scare people on the East Coast of the USA by saying a collapse of the island would send a several hundred foot high tsunami that could wipe out New York. This does have a basis in fact, however I don't think it's necessary to begin worrying about something you can't possibly predict, have no control over, and likely wouldn't happen in our lifetime. Just like all the hype about Yellowstone, Rotorua, or Toba, this is probably some information you could live without.

Also, I apologize for posting so frequently about El Hierro (even though I'm sure some people appreciate it). The Earth has been rather quiet in terms of new eruptions this month, and this one still seems to be the most exciting news. When I get a hold of any information on other eruptions, you can be assured that I will write about them!

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