Authorities issue El Hierro yellow level sismovolcánica alert for the first time in history
26 Sep 11 – The volcanic Canary Islands have experienced seismic unusual activity during the past two days, causing alarm among the population and authorities. Since Saturday there have been 48 small earthquakes on the Island of El Hierro, with the highest intensity reached magnitude 3.4 on the Richter scale. More than 7,800 earthquakes have been recorded since July 19, whereas usually the island records only ten or twelve a year. El Hierro, on the smallest island in the Canary Islands, last erupted 218 years ago, in 1793.
National Geographic Institute seismographs began recording seismic activity in El Hierro on July 19, leading scientists to ponder the possibility of an eruption. According to Nemesio Perez, coordinator of the Institute of the Canary Islands volcanological, the probability “although small, is significant.”
These earthquakes are caused by the intrusion of magma at a depth of between twelve and fourteen miles below the surface of the island.
The ground has been rising in recent days – CO2 levels increasing
The earthquakes are not the only evidence of the awakening volcano. In recent days there has been a small rise of ground, between 20 and 25 millimeters, another indicator before an eruption. A third factor is the increase in carbon dioxide levels, which are being monitored at all times.
The regional council has estimated the likelihood of a volcanic eruption at 15 percent. This was said yesterday at a press conference the president of the Cabildo de El Hierro, Alpidio Weapons, and the Minister of Security and Emergency Area, Maria del Carmen Morales. They wanted to send a message of calm, but admitted that “we know that time is special, and therefore the information should flow in its entirety, people should know first hand the situation and not have to hide anything, nor magnify” .
Being aware of the special situation of unrest and nervousness of the 11,000 residents on the island, the president of the council recommended “Tranquility, peace and calm” .
Given this increasing seismic activity, the regional government declared last Friday, for the first time in history, the yellow level sismovolcánica situation. This includes preparation of the emergency services and people with an unfavorable evolution of the earthquake in the near future.
40 years since the last eruption in the islands
The last volcanic eruption occurred in Spain in the Canary island of La Palma in 1971. It happened in the Teneguía volcano in the so-called “old peak.” Before the eruption came many earthquakes whose intensity was gradually increasing, which alerted neighbors Fuencaliente, the nearest town. The eruption was the shortest of the islands, lasting from October 26, 1971 until November 18 of that year. There were no casualties. The eruption that occurred in the National Park Timanfaya, Lanzarote, occurred in the eighteenth century and lasted six years.
This is my own interpretation of a Google translation, so you may want to read the original translation.
Thanks to Arlo Streech for this link