Tungurahua volcano – known locally as “The Black Giant” – is displaying the hallmarks of flank instability, which could result in a colossal landslide. Located in the province of the same name, the volcanco has been in an eruptive stage since 1999.
New research, led by Dr. James Hickey from the Camborne School of Mines, has suggested that the volcano’s recent activity has led to significant rapid deformation on the western flank.
The researchers believe that the driving force causing this deformation could lead to an increased risk of the flank collapsing, causing widespread, possible catastrophic damage to the surrounding area, including many communities. The research recommends the volcano should be closely monitored to watch for stronger early warning signs of potential collapse. The study is published in the journal Earth & Planetary Science Letters.
Hickey, who is based at the University of Exeter’s Penryn Campus, Cornwall, said: “Using satellite data we have observed very rapid deformation of Tungurahua’s west flank, which our research suggests is caused by imbalances between magma being supplied and magma being erupted.”
Tungurahua volcano has a long history of flank collapse, and has also been frequently active since 1999. The activity in 1999 led to the evacuation of 25,000 people from the city of Baños de Agua Santa and other nearby communities.
A previous eruption of Tungurahua, about 3,000 years ago, caused a prior, partial collapse of the west flank of the volcanic cone.
That collapse led to a wide-spread debris avalanche of moving rock, soil, snow and water that covered 80 square kilometres. Since then, the volcano has steadily been rebuilt over time, peaking with a steep-sided cone more than 5,028 meters (16,500 feet) in height.
However, the new west flank, above the site of the 3,000 year old collapse, has shown repeated signs of rapid deformation while the other flanks remain stable.
The new research has shown that this deformation can be explained by shallow, temporary magma storage beneath the west flank. If this magma supply is continued, the sheer volume can cause stress to accumulate within the volcanic cone – and so promote new instability of the west flank and its potential collapse.
Hickey added: “Magma supply is one of a number of factors that can cause or contribute to volcanic flank instability, so while there is a risk of possible flank collapse, the uncertainty of these natural systems also means it could remain stable. However, it’s definitely one to keep an eye on in the future since the lives of thousands of people could be at risk.”
Ecuador’s Geophysical Institute disputes Hickey’s findings, claiming they are based on data from 2015. Hickey responded, saying that most of his information was gatherd in November and December 2109. “I’m afraid they [the Geophysical Institute] did not carefully read the report,” he says. “I stand by my findings that the mountain poses a grave risk to those living near it from either a flank collapse or eruption. Unfortunately, history is firmly on my side in the argument.”
Credit: Heritage Daily, www.heritagedaily.com