Saturday, June 30, 2012

El Hierro Island Uplifted Several Centimeters

The earthquake swarms are continuing at El Hierro, months after the submarine eruption ended, and has caused new inflation of the island. Uplift and displacement of up to 5cm has now occurred since the beginning of the month, suggesting that deep underground, new magma is indeed being injected to the deep magma reservoir under the island. INVOLCAN scientists, according to Earthquake-report.com are staying on the island for the next 30 days, at their own expense, despite the Spanish government keeping the volcano at alert level 'green'. It seems the scientific community disagrees.

While today's activity is a bit lower than the past couple of days, the previous activity at the volcano (for those that were following it) appeared to be random and have some high and low periods of seismicity. If the same deep magma mechanism is in place, and injection is still occurring, you can expect bursts of strong activity accompanied by randomized weaker activity.

The seismicity is even in the same place as when the island built up for the last eruption. It is not far fetched at this point to assume that an eruption could be a couple of months, or even weeks away, but so far these quakes have been deep, and no new CO2 emission increases or other signs of impending volcanic activity have so far been observed. Right now all that is certain is that about 20-15km below the island, magma is re-inflating the chamber. If this continues for some time, this might indicate an eruption is about to take place again in the future. If it ceases, the magma may simply stir a while and cool slowly.

El Hierro is once again a place to watch on the list of active volcanoes.

*****UPDATE 7/2/2012******

This morning there was another hour long period of heightened seismicity, producing several quakes that were felt by residents. The new center of activity is at the NW tip of the island, partially on and partially off the coast. So far, the alert level remains the same. GPS graphs showed slight subsidence taking place BEFORE the quakes started (we are waiting for the post swarm data from Earthquake-report.com, which is one of the only blogging sites on the 'net with boots on the ground).

Earthquake activity is still much stronger than in past weeks, but currently it does not appear to be getting much stronger, and if anything, it might be getting weaker. It is still far too soon to tell whether or not the seismicity portends a future eruption of the island.

UPDATE:

Earthquake activity has returned and has now been sustained for up to 6 hours. Many quakes are above 3.0.

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