El Hierro

Nickname: Isla del Meridiano
Geography
Location	Atlantic Ocean
Coordinates	27°45′N 18°00′W / 27.75°N 18°W / 27.75; -18Coordinates: 27°45′N 18°00′W / 27.75°N 18°W / 27.75; -18
Archipelago	Canary Islands
Area	278 km2 (107.3 sq mi)
Highest elevation	1,501 m (4,925 ft)
Highest point	Malpaso
Country
Spain
Autonomous Community	Canary Islands
Province	Santa Cruz de Tenerife
Largest city	Valverde (pop. 5,797)
Demographics
Population	10,162 (as of 2003)
Density	37 /km2 (96 /sq mi)

Satellite image of El Hierro

Flag of El Hierro

Virgen de la Caridad Chapel

Mirador de la Peña, El Hierro

El Hierro, nicknamed Isla del Meridiano (the "Meridian Island"), is the smallest and farthest south and west of the Canary Islands (an Autonomous Community of Spain), in the Atlantic Ocean off the coast of Africa, with a population of 10,162 (2003).

Name[link]

The name El Hierro, although phonetically identical to the Spanish word for 'iron', is generally thought to be derived instead from one of several words in the Guanche language of the pre-Hispanic inhabitants, known as Bimbaches. Juan de Abreu Galindo (in a manuscript translated and published by George Glas in 1764) gives the native name of the island as Esero (or Eseró), meaning 'strong'. According to Abreu Galindo, the Bimbaches, not having iron originally, called the strong metal of the Spanish alternately by their own word for 'strong' and by its Spanish name, hierro, and from there transferred the alternation of names to their island.^[1] Richard Henry Major, however, in notes on his translation of Le Canarien, observes that the Guanche word hero or herro, meaning 'cistern', could easily have lapsed into hierro by a process of folk etymology.^[2] It is believed that the Bimbaches had to construct cisterns to save fresh rainwater. The Gran diccionario guanche^[3] gives the meaning of the Guanche word hero in Spanish as "fuente" ('spring [water source]').

The association with iron is evident in the names of the island in other languages as early as the 18th century: Portuguese Ferro, French l'île de Fer,^[4] and Latin Insula Ferri. Some sources,^[5][6] evidently persuaded by the meaning of Spanish hierro, imply that iron is abundant on the island, while others^[7][8] pointedly assert that it is not.

History[link]

The ancient natives of the island, called Bimbaches, were conquered by Jean de Béthencourt –more through the process of negotiation than by military action. Béthencourt had as his ally and negotiator Augeron, brother of the island's native monarch. Augeron had been captured years previously by the Europeans and now served as mediator between the Europeans and the Guanches. In return for control over the island, Béthencourt promised to respect the liberty of the natives, but he eventually broke his promise, selling many of the bimbaches into slavery. Many Frenchmen and Galicians subsequently settled on the island. There was a revolt of the natives against the harsh treatment of the governor Lázaro Vizcaíno, but it was suppressed.

Geography, flora and fauna[link]

In 2000, El Hierro was designated by UNESCO as a Biosphere Reserve, with 60% of its territory protected to preserve its natural and cultural diversity.^[9]

Like the rest of the Canary Islands chain, El Hierro is sharply mountainous and volcanic, only one eruption has ever been recorded on the island from the Volcan de Lomo Negro vent in 1793. The eruption lasted a month.

El Hierro is a 278.5 km² island, formed approx 1.2 million year ago^[10] after three successive eruptions, the island emerged from the ocean as a triangle of basaltic dykes topped with a volcanic cone more than 2,000 metres high.^[11] With continued activity resulting in the island expanding to have the largest number of volcanoes in the Canaries (over 500 cones, another 300 covered by more recent deposits), together with approximately 70 caves and volcanic galleries, including the Cueva de Don Justo whose collection of channels is over 6 km in length.^[11] Landslides have reduced the size and height of the island.^[11] The current highest point is situated in the middle of the island, in Malpaso, 1501 meters high.

Landslides and tsunami[link]

There is evidence of at least three major landslides that have affected El Hierro in the last few hundred thousand years.^[12] The most recent of these was the 'El Golfo' landslide that occurred about 15 thousand years ago, involving collapse of the northern flank of the island. The landslide formed the El Golfo valley and created a debris avalanche with a volume of 150–180 km³. Turbidite deposits related to this landslide have been recognized in drill cores from the Agadir Basin to the north of the Canary Islands.^[13] Detailed analysis of these deposits suggests that the slope failure did not occur as a single event but a series of smaller failures over a period of hours or days. Local tsunami are likely to have been triggered by these landslides but no evidence has been found to confirm this.^[12]

Coast El Golfo, El Hierro

2011 seismic activity[link]

Main page: 2011 El Hierro eruption

The Instituto Vulcanológico de Canarias (Volcanological Institute of the Canary Islands) and National Geographic Institute’s seismic monitoring station located in Valverde detected increased seismic activity beginning on 17 July 2011.^[14] The seismic monitoring network was increased in density on July 21 to allow better detection and location of the seismic events.^[14] There was an earthquake swarm with in excess of 400 minor tremors between 20 July and 24 July;^[14] by 27 July a further 320 earthquakes had been recorded.^[15] On 25 August there were reports that some horizontal deformation had been detected, but that there was no unusual vertical deformation.^[16] At that time, the total number of tremors had exceeded 4000.^[16] By the end of September, the tremors had increased in frequency and intensity, with experts fearing landslides affecting the town of La Frontera, and also a small possibility of a volcanic eruption through a new vent. Emergency services evacuated several families in the areas at most risk, and made plans to evacuate the island if necessary.^[17] Between 4.15 and 4.20am on 10 October 2011 the earthquake swarm changed behaviour and produced a harmonic tremor.^[18] Harmonic tremors are produced by magma movements and can indicate that an eruption has begun. It is thought that a small submarine eruption may have begun, 7 km south of La Restinga.^[19] As of 7 November 2011 a confirmed surtseyan type of eruption phase has started at the fissure. The eruption is currently ongoing with vigorous phreatic bubbles emerging.^[20]

Flora and fauna[link]

El Hierro is home to many unique species, such as the critically endangered El Hierro Giant Lizard (Gallotia simonyi), for which there is a captive breeding programme, allowing its reintroduction.^[9]

The interior of the island contains thermophilous juniper forest, evergreen woodlands and pine forest.^[9]

Tourism and transportation[link]

Like all of the Canary Islands, El Hierro is a tourist destination. It is served by a small airport, El Hierro Airport at Valverde and a ferry terminal, both of which connect to Tenerife.

Political organization[link]

The island is part of the province of Santa Cruz de Tenerife, and includes three municipalities:

• Frontera
• Valverde
• El Pinar

Valverde is situated in the northeast and Frontera in the southwest, both contain several villages.

The seat of the island government (cabildo insular) is in the town of Valverde, which houses approximately half of the island's population.

The "Meridian Island"[link]

Part of map of Upper Silesia (1746) with Latin message: Longitudines numeratæ à primo Meridiano per Ins[ula] Ferri

El Hierro was known in European history as the prime meridian in common use outside of the future British Empire. Already in the 2nd century A.D., Ptolemy considered a definition of the zero meridian based on the western-most position of the known world, giving maps with only positive (eastern) longitudes. In the year 1634, France ruled by Louis XIII and Richelieu decided that Ferro's meridian should be used as the reference on maps, since this island was considered the most western position of the Old World. (Flores Island lies further west, but the Azores were not discovered by Europeans until early 15th century, and their identification as part of the Old World is uncertain.) It was thought to be exactly 20 degrees west of the Paris meridian, so indeed the exact position of Ferro was never considered. Old maps (outside of Anglo-America) often have a common grid with Paris degrees at the top and Ferro degrees offset by 20 at the bottom. Louis Feuillée also worked on this problem in 1724.

Energy[link]

Assembly of the first of five wind turbines with 2,5 MW each.

According to the Ministry for Industry, Tourism and Commerce, El Hierro will become the first island in the world to be energy self-sufficient. This will be achieved through a €54 million project combining a greater than 11 megawatt wind farm and two hydroelectric projects.^{[21][22][23][24]}

The project, created by the local Gorona del Viento El Hierro consortium with financial aid from the European Union, will construct five wind turbines of type E-70 capable of producing 11.5 megawatts of wind power to supply electricity for approximately 11,000 residents, an additional number of tourists, and three water desalination facilities. The hybrid wind/pumped hydro storage system will store surplus wind power by pumping water up 700 meters (approximately 2,300 feet) to fill the crater of an extinct volcano. When winds are calm or when demand exceeds supply, water will be released from the crater to generate 11.3 MW of electricity, filling an artificial basin created at the bottom of the extinct volcano. Water in the lower basin is then pumped back up again to the upper reservoir when there is excess wind power.^[24]

The closed-loop hybrid wind/hydro system, to be tested by the end of 2012, is expected to save approximately US$4M per year (calculated with January 2011 oil prices) currently spent on about 40,000 barrels of crude oil imported annually, and will make the island completely self-sufficient for electrical energy.^[24]

El Hierro in literature[link]

The island of Hierro is mentioned in Umberto Eco's novel "The Island of the Day Before" ("L'isola del giorno prima", 1994), a novel about a 17th century Italian nobleman trapped on an island on the International Date Line.

See also[link]

• List of volcanoes in Spain
• Prime meridian

Notes[link]

External links[link]

• El Hierro - official tourism website of the Canary Islands
• 4D model of earthquake swarm July to September 2011

Scientific links[link]

• Global Volcanism Program, Smithsonian Institute
• James M. Day, e.a.: Evidence for distinct proportions of subducted oceanic crust and lithosphere in HIMU-type mantle beneath El Hierro and La Palma, Canary Islands, 2010 (Science Direct, PDF)
• Martin J.R. Gee, e.a.: Landslides and evolution of El Hierro in the Canary Islands, Marine Geology 177 (2001), 271-93 (PDF)
• M. R. Gee, e.a.: Offshore continuation of volcanic rift zones, El Hierro, Canary Islands, Journal of Volcanology and Geothermal Research, 105 (2001), 107 - 119 (PDF)
• F.G. MONTESINOS: New study of the local gravity field of El Hierro (Canary Islands), Física de la Tierra, 2005, 17, 113-127 (PDF)
• Longpre, M.; Troll, V.; Hansteen, T. H.; Anderson, E.: Ankaramitic Lavas and Clinopyroxene Megacrysts From the Tanganasoga Volcano, El Hierro Island (Canary Archipelago), American Geophysical Union, Fall Meeting 2009, abstract #V51A-1662, Publication Date: 12/2009 (Abstract)
• N. A. Stroncik, e.a.: The magmatic plumbing system beneath El Hierro (Canary Islands): constraints from phenocrysts and naturally quenched basaltic glasses in submarine rocks, Contrib Mineral Petrol (2009) 157:593–607, DOI 10.1007/s00410-008-0354-5 (PDF)
• J. J. Hernandez, e.a.: Volcanic caves in El Hierro island, Canary Islands, Spain (PDF)
• J. de Nuez Pestana, e.a.: Geology and volcanology of La Palma and El Hierro, western Canaries , Estudios geológicos, Vol. 57 no.56, 175-273 (Abstract)
• Serie Sísmica de El Hierro, Grúpo de Investigación de Ingeniería Sísmica, Universidad de Madrid , act. 29.9.2011 (Spanish)

Photos and Videos[link]