Volcanic Alert In Effect On El Hierro
This is not good news at all - especially if you live on the east coast of the USA!!
Volcanic Alert In Effect On El Hierro As 4.3 Magnitude Earthquake HitsBy Mark Dunphy - Sun Oct 09, 1:59 pm
Epicentre of Saturday night's earthquake on El Hierro. Image Google Maps
A 4.3 magnitude earthquake struck El Hierro, the smallest of The Canary Islands, late on Saturday night. It was the strongest earthquake to be recorded on the Spanish island since an unprecedented earthquake swarm commenced during the summer.
The Instituto Geografico Nacional (IGN) has reported an increase in the intensity of earthquakes recorded on El Hierro, the smallest of The Canary Islands, during the last 48 hours. The number of earthquakes recorded since July 17 , 2011 on El Hierro has now reached 10,000, figures from the IGN confirm.
The IGN also confirmed surface deformations exceeding 35mm on the 280-sqkm island, where residents have been put on alert for a possible volcanic eruption. However, seismologists have moved to reassure the local population that a volcanic eruption is not imminent.
The agency confirmed on Friday that 886 earthquakes, most of them located in the sea to the SW of the island, have been recorded in the 7 days since 02 October, 2011. During this period, 71 earthquakes were felt by the island’s estimated 10,000 residents.
Since Friday morning, there have been more than two dozen earthquakes exceeding 3.0 on the Richter Scale with epicentres both North and South of the NW Ridge and depths between 10 and 15 km have been recorded. The strongest of the tremors measured 4.3 magnitude on the Richter Scale, many times stronger than other earthquakes recorded on the island since mid-July. It was recorded on Saturday night at a depth of 12 km. The quake produced small rockslides but no injuries were reported.
Hierro, a shield volcano, has had a single historic eruption from the Volcan de Lomo Negro vent in 1793. The eruption lasted approximately one month and produced lava flows.
The recent surge in the number and intensity of earthquakes prompted officials from the IGN and The Canary Islands Government to raise the alert level for the Hierro volcano to ‘Yellow’ late last month. The alert remained in place on Sunday.
Seismologists say the majority of the earthquake activity has shifted from El Golfo in the island’s northwest to beneath the Las Calmas Sea in the south.
However, magma is now on the move upwards while the depth of earthquakes has become increasingly shallow in recent days with most being recorded at a depth of 9 to 14 kilometres. Movement of magma towards the surface signifies that a volcanic eruption is likely to happen, but the timing of such remains unclear.
Volcanologist Juan Carlos Carracedo last week suggested that an eruption on El Hierro would “not be a major surprise”. He explained: “It is the youngest of the Canary Islands. There is a ball of magma which is rising to the surface and it is stationed at the limit of the earth’s crust. At the moment we do not know if that ball of magna will break the crust and cause an eruption.”
IGN Director, María José Blanco said that any eruption on El Hierro would most likely have a “low explosion value”.
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