Updated 15 June 2018: There has been a bit of activity in El Hierro over the past week after a couple of years in which the island’s seismic activity has barely registered for vulcanologists or media! Over the past day and a half, however, there have been seven tremors felt around the south and gulf area of the island, all between 29 and 34km deep, the largest being 3.5 on the Richter scale. IGN says that none of the latest activity has been felt by the public, and that although it is “odd”, it is within the framework of the island’s general volcanic activity over the past several years. No other anomalies that could suggest an eruption is possible, like deformation, geochemical gases, etc., have been detected though monitoring work is ongoing.
Updated 20 April 2016: It’s been very quiet in El Hierro for the past year, and indeed the last post I made here was almost exactly a year ago, but El Hierro experienced an earthquake just after 1.30 this lunchtime of 4.2 on the Richter scale. This is the island’s largest since since a 5.1 was registered in December 2013, being felt in other islands including Tenerife as well. Today’s quake occurred at a depth of 26km, with its epicentre just off the Valverde coast in the north. It was felt throughout the island, significantly so in some areas, though no damage has been reported.
Update 7 April 2015: Another tremor was registered around 4pm this afternoon in the same area as the 3.1 registered nine days ago. That one, which was always thought to be stronger than a 3.1, has subsequently been reclassified as a 3.7, and today’s was a 2.7 at a depth of 11.3km and was felt by some of the public. This is all in the area south of La Restinga where the main eruption has taken previously.
Update 29 March 2015: It has been quiet for six months or so, but around 5am this morning a strong tremor was recorded at the southern tip of the El Pinar area of El Hierro. Actualidad Volcánica de Canarias (AVCAN) says that although the strength has been reported by IGN as a magnitude 3.1, seismographic readings and the extent to which is was felt – throughout the whole of the island – suggest that it was stronger.
Update 4 September 2014: An earthquake of 2.4 on the Richter scale at a depth of 33 km was registered by IGN to the west of El Hierro last evening minutes before 8pm. It was followed at 10.36pm by another of 3.8 at a depth of 15.6 km in the same region. Avcan (Actualidad Volcánica de Canarias) says that it was felt throughout the whole of the island.
Update 15 March: The cluster is now a swarm, with the largest tremor overnight at 2.4 on the Richter scale. All the quakes are said to be deep at 15 and 20 km, and have slowly shifted north from the El Golfo area towards Valverde and then turned back south towards the centre of the island, towards an area previously unaffected. This fits experts’ views that the magma is continuing to seek new ways of reaching the surface. Over the last hours of the night the rate of tremor increased, with some 227 being recorded over the last 24 hours
Update 14 March 2014: Avcan is reporting a new magma intrusion in El Hierro which has resulted in some 25 tremors since early this morning. Seismic activity has been building up somewhat over the past few days, but as of 5am this morning a cluster of earthquakes has been recorded, almost all of them between 1.8 and 2.3 on the Richter scale. All were located in the eastern wall of the Golfo area of the La Frontera municipality, between the Roques de Salmor to the los Roquillos tunnel.
Update 28 December: Further quakes of 3.7 and 3.3 were recorded last night (11pm and just before 1am) in the same place (10km out to sea to the west of El Hierro) at depths of 20 and 12 km. These are just the “relatively strong” ones – several others in the mid-2 Richter range were also registered Deformation in the El Pinar and La Restinga area is now said to be “strong”, giving a total lift of 10cm in this cluster.
Update 27 December: A widely-felt earthquake in El Hierro this afternoon has been confirmed by IGN 5.1 on the Richter scale. It was also felt in the north of Tenerife and La Palma. The earthquake was at 5.46pm to the west of the municipality of Frontera, at a depth of 15km. It was widely felt and locals, said to be alarmed, described the effect as a very strong shaking. Five minutes later another two tremors of 2.9 and 2.7 on the Richter were recorded, though these weren’t felt by the public.
Update 23 December: There have been 121 earthquakes over 1.5 on the Richter scale in the last 24 hours, all of them at a depth of around 14km. Vulcanologists say that a new episode of magma eruption has now started, confirmed by deformation data supplied by Involcan: upward deformation is at least 2cm. At present, the tremors have headed to, and are clustering below, the El Pinar area (red on the above IGN graphic). Seismologists say that at the present depth, there is no immediate danger, but that quakes are expected to grow stronger. Depending on the magma’s success in gaining release, too, the movement may change direction. Watch this space, as they say.
Update 22 December 6pm: And in the last hour, two have been registered over 3 on the Richter scale, and I’ve just received an email from Bob in El Hierro (has posted in my comments) who says that they are “having another house shaking session, two felt in Valverde around 16.30 hours”.
Update 22 December 2013: It’s been fairly quiet of late, indeed over the last few weeks it’s been very quiet indeed, but it’s woken up to give a Christmas message. A new cluster of tremors has been registered over the past 24 hours which experts say looks like a preliminary to something stronger. The activity started in the Mar del golfo (see the green dots in the above image) with 11 tremors at a depth between 14 and 16 km, and then started to move under the island over the last several hours (red). The highest tremor recorded at present is 2.8 on the Richter scale: vulcanologists say that the magma is still trying to find a way out.