Major New Andes Tunnel Turns Back on Volcano

By an IPS Correspondent Reprint | | Print |

FINCA GALICIA, Cordillera Central, Colombia, Oct 26 2013 (IPS) - 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.

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.Quick look at what would happen if the Machín volcano erupted:

* One million people directly affected
* Permanent relocation of the population from the area at risk
* The western and central parts of the country completely cut off
* Three important farming areas destroyed: Cajamarca; part of the province of Quindío; and the Tolima valley irrigation district
* Nearby towns covered with a layer of ash at least half a metre thick

“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.)

Even the smallest eruption by Machín would be larger than the eruption of the Ruiz volcano, 45 km to the northeast, which in November 1985 spewed out 0.3 cubic km (km3) of lahar – mudflow or debris flow – which destroyed the town of Armero, killing 22,000 of its 28,000 inhabitants and leaving over 5,000 injured.

“Machín’s normal eruptions can cover several cubic kilometres. And the big ones have been approximately 20 km3,” Calvache said. If the next one is big, “it will affect the entire central area of the country,” including parts of the provinces of Tolima, Quindío, Valle del Cauca and Cundinamarca that are home to nearly one million people combined, the geologist warned.

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.

“That change, in human terms, would be forever. It would be human beings who would have to adapt,” she 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.”

The authorities are apparently betting on the latter.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.

The government of Álvaro Uribe (2002-2010) declared the La Línea route “strategic” in 2005. La Línea is essential for trade between Cúcuta, the main city on the border with Venezuela, in the northeast, and Colombia’s only Pacific Ocean port, Buenaventura, in the west. The road runs through the wealthiest part of the country, the central highlands, where Bogotá is located.

“All of the freight that reaches Bogotá from the Pacific comes through here,” Luis Orlando Muñoz, the head of the Colombian Society of Engineers (SCI), told IPS. “Thousands of tonnes of imports and exports are transported daily. This is the country’s spinal column, when it comes to roads.”