Juan Jose Dalton & Gerardo Arbaiza
SAN SALVADOR (dpa) – Tiny El Salvador has volcanoes the way a classroom has desks: the tiny Spanish-speaking nation on the coast of the Pacific Ocean is full of them.
Despite the potential danger, no one pays them much mind. Salvadorans build their homes on the sides of volcanoes and plant crops such as maize and beans just where the next disaster might be looming.
Some enterprising Salvadorans have even created a tourism specialty: taking visitors right inside volcanoes, such as exploring the scenic, jungle-clad interior of the El Boqueron crater. Crops are grown on the rim.
There is no cause for alarm, they say. It has not erupted since 1917.
With a surface of just over 21,000 square kilometres, El Salvador is the smallest nation in Central America. Nonetheless, it is home to 170 volcanoes, of which 14 are active and six are constantly monitored because of fear they could erupt.
Still, the country has more pressing problems than magma and superhot gas: it is also being eroded by rain, because its mountains and hills have suffered extensive deforestation.
At the most recent international conference on climate change, held in Qatar two years ago, experts issued a warning to El Salvador, saying that over 80 per cent of its territory is vulnerable to landslides during the rainy season, which happens every year, far more often than eruptions.
Eduardo Gutierrez, a volcanologist with the Salvadoran Environment and Natural Resources Ministry, told dpa that the volcanoes have arisen and continue to be created in El Salvador because it is located where two tectonic plates meet.
One of them is the Cocos tectonic plate, a tectonic plate beneath the Pacific Ocean, located 50 kilometres offshore.
The other one is the Caribbean plate, which is a mostly oceanic tectonic plate underlying Central America and the Caribbean Sea. El Salvador is located at the line where they collide, said Gutierrez.
“When these two plates run into each other, it creates faults and cracks, through which magma can rise to the surface. That’s a volcano,” he explained, adding that most of the volcanoes in El Salvador are distributed along lines parallel to the fault where the two tectonic plates meet.
According to geological studies carried out locally, most of the volcanoes began 10,000 years ago. However, there is evidence of volcanoes that emerged approximately 100,000 years ago further north, on the border with Honduras and Guatemala.
Gutierrez explained that volcanoes are divided into two types, depending on how they were formed: polygenic and monogenic. Polygenic volcanoes are formed in layers produced by various eruptive cycles, as for example the Santa Ana or Ilamatepec volcano, El Salvador’s tallest with a summit 2,381 metres above sea level.
Monogenic volcanoes are created by a single eruptive cycle and have small volcanic cones.
The eruption in El Boqueron in 1917 left a small cone inside the main crater.
Gutierrez said that once a volcano completes an eruptive cycle, fissures through which magma flowed out solidify again.
“The next eruption will find a great deal more resistance and will happen at a new site. That is why we see volcanoes that are perfectly lined up in a specific area.”
Authorities keep constant watch over six of the country’s volcanoes: Santa Ana, Izalco, San Salvador (which contains Boqueron), Caldera de Ilopango, San Vicente and Chaparastique.
Gutierrez said those volcanoes are monitored because of their histories: some have had huge eruptions, among them the Caldera de Ilopango which flooded and is thus often called Lake Ilopango. This volcano spewed out 84 cubic kilometres of volcanic material when it erupted 1,500 years ago.
Those six volcanoes also continue to show seismic activity within them, their craters are well defined and in some cases they give off plumes of vapour.
Historical records show that when the Spanish conquistadors arrived in the region round the capital San Salvador at the start of the 16th Century, they dubbed it the Valley of the Hammocks, a sly reference to the constant rocking of the ground because of tremors.
Over the last 10 years El Salvador has experienced two large eruptive events. On October 1, 2005, Ilamatepec erupted. Chaparrastique went off on December 29, 2013. Both eruptions were of ashes and gases; not lava.
Before the 2005 eruption, Ilamatepec, located in western El Salvador, had not erupted in 100 years. Gutierrez said that the volcano had not stopped being active, but had returned to a non-eruptive phase.
Chaparrastique, in the eastern province of San Miguel, is one of the most active volcanoes in El Salvador. Prior to the 2013 eruption, it had erupted in 1976.
Gutierrez remarked, “One must never go near volcanoes when they are erupting. But afterwards, they are life givers.”
He was referring to the fact that volcanic ashes are rich in nutrients and fertilise lands to produce a bounty of beans and other crops.