Post date: Feb 02, 2011 1:44:3 PM
Scientists assess threat posed by a possible eruption of Mexico's rumbling "Fire Volcano," in Colima, one of the biggest and most threatening in the northern hemisphere. The Colima volcano has erupted 40 times since 1576.
LA YERBABUENA, COLIMA, MEXICO (RECENT) REUTERS - Mexico's rumbling 'Fire Volcano,' in Colima is being closely monitored by vulcanologists who say it has shown a lot of activity since the 1970s. Despite some quiet periods, they say a dome being formed within its crater has become unstable as it rises and
could collapse at any given moment.Western Mexico's rumbling "Fire Volcano," it is not expected to erupt in the near future but it is active and some of its walls have collapsed but material has not yet reached nearby-towns.
Resident, Jesus Montejano, from the town of La Yerbabuena in Colima state, which lies on the skirts of the volcano, said he has seen and heard constant activity.
"It's (volcano) been active. Some walls have been collapsing because one can hear and see them. I have a plot of land up there and I see the movements throughout the day."
Vulcanologists and civil protection authorities flew over the mountain, also known as the Colima volcano, on October 13 last year and reported no changes in the height of the dome as well as the area covering the surface of the crater.
The volcano has not registered any changes in its activity in the last couple of months but collapses of accumulated matter have occurred on its southern, northern and western sides.
A monitoring project called "Fire Giant" at the Volcano Observatory, which is part of Colima University, is constant because high degrees of explosiveness could generate an eruption of immense proportions. Volcano matter could represent a great threat because it could reach distant areas, according to vulcanologists.
Scientists have based their project on the volcano's last large explosive eruption that took place on January 20, 1913 which lasted four days. Ash flows characterized the eruption which left a crater measuring 300 metres in depth.
"We have based most of our forecast model on the (volcano's) behaviour in 1913. The risk and danger map is focused on that last scenario, the huge one in 1913 where we had flows extending 15 kms, falling of ash spreading more than 500 kms. Obviously an event with those characteristics would currently bring economic consequences, above all," volcano researcher from Colima University, Juan Jose Ramirez, said.
After 1913, the volcano remained dormant for 44 years before it became active again. Eruptions with lava as well as more violent ones were registered in 1961, 1987 and 1994.
Vulcanologists are expecting the destruction of the dome. The volume of volcanic material would be large and would affect local surrounding communities. The worst affected area is expected to be the one lying close to the southern slopes because northern slopes are reinforced by older geological structures, vulcanologists said.
A resident from Yerbabuena, Rafael Sandoval, said fuming has not stopped.
"The fumes. Sometimes they are bigger that the ones before. It hasn't stopped. I don't understand where it expels material from."
Scientists working at the Geosciences Centre based in the town of Juriquilla in Queretaro state, which is part of the National Autonomous University (UNAM), said gravity alone could cause the dome to collapse.
"At the moment the dome on top is a few years old, from 2007 to 2008 and it hasn't disappeared yet, it continues to grow and it is now on top of the crater. It's (dome covering volcano) showing unstable conditions which at any time, even due to gravity, could collapse and generate what is known as pyroclastic flows. In the best case scenario, it would only be gravity what would conduct the 'materiel" though near-by ravines," said the Director of the Geosciences Centre from UNAM University, Gerardo Carrasco.
If a more explosive eruption took place, dense clouds of ash could form quickly and there would be no time to warn the population.
"But the gas concentration could lead to another more explosive scenario where we would have to consider evacuations and preparedness for more serious conditions," Carrasco added.
In 2005, forty-five people were evacuated from a hamlet near the volcano, which is the most volatile it has been in more than a decade. The volcano, spewed ashes almost 3 miles (5 km) high, its fiercest eruption in more than 15 years.
The 12,540-foot (3,860-metre) Fire Volcano, located in a sparsely populated rural area, has been Mexico's most active volcano in recent years.
Villagers were also evacuated from the area in 2002. Another volcano, Popocatepetl, stands near Mexico City, home to some 20 million people.