A new system of tunnels at the Alto de La Línea mountain pass in Colombia’s central Cordillera mountain range will open up a key logistics route for this country and neighbouring Venezuela. But it could be overcome by disaster if the Machín volcano erupts.
The complex engineering feat includes two main one-way tunnels, 8.8 and 8.6 km long, as well as 21 short tunnels and 29 viaducts that will total 6.8 km in length. The first of the main tunnels, which will be the longest road tunnel in Latin America, is to be completed by mid-2014. The firms that will build the second tunnel have not yet been selected.
Danger: volcano ahead
But in the department (province) of Tolima, the road passes six km from an unassuming hill which is actually the Machín volcano, one of Colombia’s most dangerous volcanoes, which has erupted six or seven times in the past 10,000 years. The most recent eruption occurred around 800 years ago.
“The most explosive volcanoes remain quiet for long periods of time,” said Marta Calvache, director of the Colombian Geological Service (SGC).
The SGC – formerly Ingeominas – drew up the first hazards map for the Machín volcano in 1998, which it amplified in 1999, 2000 and 2003. The map recommends that the hazards posed by the volcano be taken into account in decision-making on “strategic medium and long-term plans for routes, especially roads.”
The La Línea tunnel and the Machín volcano are 15 km apart as the crow flies. If the volcano erupts, “the tunnel will be left without a road,” Calvache told IPS.
More than 100 monitoring stations keep an eye on the volcano 24/7. In 2008, authorities declared a yellow alert, which is still in place. (Green is for normal, yellow for alert, and red for warning and evacuation.)
The Machín volcano’s eruptions “produce major pyroclastic flows (a fast-moving current of hot gas and rock). No one survives a pyroclastic flow, and the basin would be completely changed,” Calvache said.
“The volcano has been changing,” she added. “What we don’t know is whether that change is headed towards an eruption or if it is simply being unruly and will go back to being calm again for many years.”
In the environmental impact assessment for the tunnel, “Machín isn’t mentioned as a risk factor,” environmentalist Néstor Jaime Ocampo, of the Cosmos Ecological Foundation based in Armenia, the capital of Quindío, told IPS.
Source: Constanza Vieira | IPS News