By Juana Casas
SANTIAGO (Reuters) - A towering ash cloud spewing from a volcano in south-central Chile could disrupt air traffic for some time as the eruption shows no signs of stabilizing in the near term, experts said on Tuesday.
Ash from a volcano in Chile's Puyehue-Cordon Caulle chain that erupted on June 4 after decades lying dormant reached as far as southern Brazil, and has forced the sporadic cancellation of hundreds of local and international flights, particularly in neighboring Argentina.
Flights as far away as Australia have been grounded because of the ash, which can damage jet engines.
The ensuing chaos has buffeted airlines including Chile's LAN as well as Brazil's TAM and Gol, which halted services to and from Buenos Aires.
"There are no signs that the situation is going to change or stabilize in the short term", said Enrique Valdivieso, director of Chile's national service of geology and mining (Sernageomin).
"Fine ash, like we have seen from this latest eruption, could last (in the air) for months. If the ash column continues to measure up to 5.5 miles, it can spread easily. The higher the ash, the more it is blown elsewhere."
He said it was hard to predict how long the ash cloud would continue to affect flights. If the volcanic eruption intensifies, it could increase the amount of ash belched into the atmosphere.
Airports in Buenos Aires were set to gradually reopen on Tuesday night as the ash cloud dissipated. As of 5:00 p.m. local time only one flight had landed at the Argentine capital's main airport and most airlines were keeping flights grounded.
Air travel in northern Europe and Britain was disrupted last month after Iceland's most active volcano at Grimsvotn sent a thick plume of ash and smoke 15.5 miles into the sky.
In April last year, the eruption of another Icelandic volcano, Eyjafjallajokull, led to 100,000 canceled flights, affecting 10 million people at a cost of $1.7 billion.
Chilean volcanoes tend to spew more ash than European volcanoes like Iceland's, because the magma is thicker and rises more slowly. As a result more ash is expelled.
"If we take the case of Chile's Lonquimay volcano in 1989, the plume lingered for about two months," said Felipe Aguilera, a volcanologist at Universidad de Atacama.
Ash has drifted as far as New Zealand and Australia, forcing airlines such as Qantas Airways Ltd and Virgin Australia to cancel and delay flights.
Brazilian authorities reported that the volcanic ash reached the southern cities of Porto Alegre and Florianopolis.
It was the latest in a series of volcanic eruptions in Chile in recent years. Chile's Chaiten volcano erupted spectacularly in 2008 for the first time in thousands of years, spewing molten rock and a vast cloud of ash that reached the stratosphere. The ash also swelled a nearby river and ravaged a nearby town of the same name.
The ash cloud from Chaiten coated towns in Argentina and was visible from space.
Chile's Llaima volcano, one of South America's most active, erupted in 2008 and 2009.
Chile's chain of about 2,000 volcanoes is the world's second largest after Indonesia. Some 50 to 60 are on record as having erupted, and 500 are potentially active.
(With reporting by Maximiliano Rizzi and Luis Andres Henao. Editing by Simon Gardner and Eric Walsh)