It has been a few months now since the eruption at El Hierro in the Canary Islands was declared "over". There may be some passive degassing on the seafloor from the new vent that formed at depth to the south of the island, but things had settled down. Even the people of Restinga were putting the eruption in the past, with both webcams taken offline and the guarantee of €600,000 (~$750,000) from the government to aid fishermen whose livelihoods had been altered by the closed fisheries.
However, with any active volcano, it can be difficult to predict when exactly an eruptive cycle is truly done. Over the last few days, seismicity under the island has resumed and its manifestation is very similar to what we saw last summer during the lead up to the eruption of El Hierro in October 2011. Over 50 earthquakes have been recorded at El Hierro, some as large as ~M3.5 and AVCAN thinks that the new seismicity suggests that magma is moving in the same conduits as the fall 2011 activity. The earthquakes are, as of now, still deep - upwards of 15-25 km below the surface. This likely supports the idea that there is new magma entering the El Hierro system at depth. Now, last summer it took months of constant seismicity before we saw any surface manifestation (the submarine vent at ~88 meters depth), so we may not know if this new intrusion of magma will lead to new eruptions until the fall. {Special thanks to Eruptions readers for a number of links and images in this post.}
Image: IGN.es plot of seismicity under El Hierro for June 24-25, 2012.
