Monday, December 30, 2013

El Hierro Volcano Alert Raised To Yellow

It seems as if PEVOLCA has decided to raise the alert level at El Hierro yet again to yellow after a spate of larger earthquakes measuring up to 5.1, and inflation totaling about 3-4 inches has occurred on the island volcano. earlier this week I had reported that Earthquake-report.com's El Hierro blog was noticing a sharp increase in deformation and seismicity.

This swift a rise in seismicity and deformation is attributed to new magma injection, but whether or not it will again find its way to the surface remains to be seen. It is however becoming more and more likely that this is the case if the trend continues. The inflation of the island at its current state is greater than when it had its offshore submarine eruption off the coast of the fishing village called La Restinga.

The eruption was closely watched by scientists, and geeks like me, who were 'hoping' for the eruption to transition from the submarine Serretyan phase to a more prominent island building phase called a Surtseyan eruption (after the volcano Surtsey in Iceland, which was one of the first islands to be observed in its moment of creation by modern volcanologists). The web camera set up by Earthquake-report.com, and some others were a source of spellbinding anticipation at least on my end.

The deformation so far bisects the island down the middle (as shown in the link), and it is anyone's guess where the island may choose to vent its payload. The area with the greatest uplift (as of today, 3CM in less than a week!) is the NE town of Sabinosa, which is built directly on the remnants of a cinder cone.
The island is dotted by many holocene to pliestocene cinder cones, as well as a collapse-related pseudo caldera, as well as its more recent and older submarine cones. Predicting where the island may erupt is next to impossible, but very hopefully it will erupt in an area that is not populated, or is remote enough for people to evacuate in time. The island does not have a heavy permanent population, but it is a popular tourist spot in the region.



Video showing rockfall on El Hierro.

Some hazards are occurring due to the unrest. Rockfalls are a very real problem for the various roads and homes that lie at the bottom of cliff faces, and some have already ruined or blocked some roads. So even though an eruption isn't occurring, and the quakes are small, it is still creating some problems.



As always, I will keep an eye on this volcano and post updates when they occur. This is one of my very favorite volcanoes to observe lately, so you'll probably see a few more of these posts.

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