Philippine volcano rumbles, eruption seen soon

A column of ash shoots up to the sky in a mild eruption of the cloud-covered Mayon volcano in Legazpi City, Albay province, south of Manila December 23, 2009.

LEGASPI, Philippines (Reuters) - The Philippines' most active volcano shot higher ash columns and rumbled louder on Wednesday as authorities warned of a potential hazardous eruption in Mount Mayon anytime.

Mayon Volcano, known for its near-perfect cone shape in the coconut-growing central Bicol region, has been spewing ash and burning mud and rocks for more than a week. Officials have evacuated nearly 50,000 residents from around the base of the volcano.

President Gloria Macapagal Arroyo flew on Wednesday to Albay province where Mayon Volcano is located to inspect the government's disaster preparedness plan. She briefly talked to some of the evacuees and handed out relief goods.

Authorities said they monitored distinct indicators of a hazardous eruption, such as continuous lava flows, rumbling sounds and ash explosions coupled with sulphuric dioxide emission from the volcano.

"We can't exactly predict when the big bang will come, but the volcanic activities are getting more intense from the time we raised the alert level to 4 on Sunday," the state's chief vulcanologist, Renato Solidum, said, adding stronger tremors were felt on Wednesday and gas emissions were increasing.

"We're ready to raise the alert to the highest level if we start to see a hazardous eruption, characterized by taller ash columns, extensive ashfalls and pyroclastic materials racing down on the slopes."

Level 4 indicates an eruption is imminent and the maximum alert level 5 means a dangerous eruption is underway.

A major eruption is not expected to impact the country's farm output with mostly subsistence farmers tilling the land around the volcano. An eruption will not have any impact on industry either as there is no major industry in the area.

But an eruption could boost local tourism as travelers head to Albay like they did during Mayon volcano's last eruption in 2006. Mayon's most destructive eruption was in February 1841, when lava flows buried a town and killed 1,200 people.

Troops enforced an extended 10-km (5-6 mile) no-go zone, patrolled the area and imposed a 24-hour curfew to prevent people from returning to their homes and farms. Army medical teams were also sent to shelter areas.

(Reporting by Manny Mogato; Editing by Rosemarie Francisco and Sugita Katyal)