According to the National Geographic Institute of Spain
, increases in seismic activity on the island has seen literally hundreds of earthquakes, known as a swarm, shaking the island and gradually increasing in strength since June 25. Around 750 earthquakes have been recorded although few have been strong enough to be felt by the residents until the last two days
The island has been placed on yellow alert by the security committee in charge of operations as the earthquakes increase. The largest so far was registered at 4.0 on the Richter scale on Wednesday June 27.
More frightening for the approximately 10,000 residents is the fact that a bulge has developed
in the island, lifting it five centimetres in four days. Whereas the volcanic activity of 2011 was based out at sea, this time the magma appears to be forming right underneath the island and the pressure is building. Scientists on the island are using the position of the earthquake epicentres to try and work out where the magma from the volcano will come to the surface.The longer it takes to find a vent, the more the pressure from the magma will grow and the larger any possible eruption is likely to be.
says that PEVOLCA (Civil Protection from Volcanic Risk) has said that there is an acceleration in the flow of magma, with a "clear process of inflation".
As reported by Digital Journal
on June 25, the island suffered serious seismic activity last year, resulting in an undersea volcanic cone as can be seen in the video. However, over time, the activity died down and it was thought by experts that was the end of the event. The research vessel 'Hesperides' which had been investigating went home and the live cameras were turned off. Now the 'Hesperides' is hurrying back to the island but the cameras have not as yet been turned back on.
The website Decoded Science
, in an article by Jennifer Young, explains how magma chambers work and how scientists are processing information from volcanoes to learn more about predicting possible eruptions. It is this activity that the scientists on the 'Hesperides', in conjunction with those on the island itself, will be studying in an effort to try and predict if and when the volcano under El Hierro will erupt.
Official reports have been few and far between and the Spanish media has concentrated rather more on the football and the economy than the volcano growing under one of Spain's most popular holiday destinations, just as the season gets into full swing.