Chilean volcano belches ash, forces evacuation

(Government revises identity of volcano paragraph 5)

SANTIAGO, May 2 (Reuters) - A volcano in southern Chile spewed a vast cloud of ash before dawn on Friday, triggering earth tremors and prompting the evacuation of about 250 people, officials said.

Residents said ash fell over the picturesque Patagonian town of Chaiten, which is 760 miles (1,220 km) south of the capital Santiago and just 6 miles (10 km) from the volcano.

Trucks with drinking water were being sent to the area after ash affected water supplies, local authorities said. School classes were suspended in some areas and hospitals treated people for irritated eyes and breathing difficulties.

"We felt the movements and can see the ash falling in town," Sara Ruiz, a receptionist at municipal offices in Chaiten said by telephone.

The national emergency office and residents initially identified the source of the ash as the volcano Michimahuida, but later said it was Chaiten, which has the same name as the nearby town.

President Michelle Bachelet said in Santiago: "Chile is a volcanic country, and I want to say that we are working and coordinating all our might at a local and national level and call for calm," she said in Santiago.

Across the nearby border in Argentina authorities in Chubut province advised residents not to rub their eyes and to wear glasses and long sleeves to avoid ash making contact with skin.

Another Chilean volcano Llaima, one of South America's most active, erupted violently on New Year's Day, spewing ash and molten lava and forcing the evacuation of dozens of tourists and staff from a wilderness park.

Llaima, which is about 435 miles (700 km) south of Santiago, also belched ash in February and a river of lava crept down its slopes. (Reporting by Antonio de la Jara and Simon Gardner. With reporting by Cesar Illiano in Buenos Aires; Editing by David Storey)