Nearly 100 earthquakes were recorded on El Hierro on Easter Saturday, two of them felt by the population, according to the National Geographic Institute (IGN) volcanic surveillance network. Although not as intense as in previous days, the epicentres have again shifted direction and now appear to be heading east, back toward the El Hierro coast.
This latest earthquake swarm has shaken the island daily since March 18th, with news starting to emerge of scientists having detected a large magmatic intrusion beneath the island which is suspected to be highly mobile. This has led to building pressure and, some say, the potential of a further eruption as CO2 levels start to climb, just as had happened before the 2011 submarine eruption which lasted just over 100 days and ended almost exactly 1 year ago near the fishing town of Restinga, causing a bubbling cauldron visible on the surface which produced magmatic material just off the southern coast of this the western most Canary Island,and creating a large discoloured stain in the sea which could be photographed from outer space.
Below here you will see two different animations built from the recorded position of the various movements that have been detected most recently giving you some of idea of where the current activity has been centred:
So far, the strongest tremor of the weekend was measured at 4.3 degrees, just west of the town of La Frontera at a depth of about 19 miles and could be felt by the inhabitants of the island.
Throughout Good Friday the small island had anything up to 189 earthquakes, including many over 4.0 and one that reached the 4.7 degrees on the Richter scale with a magnitude of III in the EMS scale, making it the largest quake since this latest activity began. During the night there were three other movements that exceeded 4 degrees, but only one was felt by the islanders, with reports of the largest quakes being felt on El Hierro’s nearest neighbour, the island of La Palma.
Since then there have been more than 40 new shocks, 13 of which have exceeded magnitude 3, and the rest having ranged between 2 and 3 degrees on the Richter scale.
The Canary Islands Civil Protection Planning committee for Volcanic Risk (Pevolca) have raised the seismic risk alert level to yellow on part of the island and limited movement in areas that may be exposed to rockfalls due to the continuing shocks.