LEGAZPI CITY?A power blackout was enforced Thursday in the danger zone around restive Mayon Volcano as authorities warned that the full moon on New Year?s Day could trigger a big explosion.

Resident volcanologist Eduardo Laguerta said the volcano?s behavior indicates a major eruption in the offing, especially when the moon is full?a possible triggering mechanism for a volcano that is ready to explode.

The gravitational effect when the moon is full and near the Earth could speed up the ascent of magma out of the volcano, other volcanologists agreed, but Director Prisco Nilo, head of the Philippine Atmospheric, Geophysical and Astronomical Services Administration (Pagasa) said the theory was controversial.

At any rate, Albay Gov. Joey Salceda ordered the Albay Electric Cooperative (Aleco) and the National Power Corp. (NPC) to cut power supply in villages within the danger zone in order to stop residents from returning.

Salceda said water supply may be turned off Friday.

Eruption tourism

Lt. Darwin Nieva, spokesman of the Regional Disaster Coordinating Council, confirmed reports that residents, farmers and even tourists were trekking up the volcano?s slopes, noting Mayon?s unusual calm over the past days.

Soldiers caught 15 foreign tourists allegedly brought to the lava front in Barangay Mabinit by a Legazpi City councilor who engages in tour packages.

Reacting to these reports, Salceda said: ?We are awaiting the result of the investigation by the Philippine National Police and we will base our next action on it.?

The governor said a lot of evacuees had returned to their homes for the New Year?s celebration.

Salceda said he ordered the power cut to stop residents from returning to the danger zone, where a 24-hour curfew has been declared.

Jose Buenafe, Aleco president said the company began switching off electricity at 10 p.m. on Wednesday. The blackout was 80-percent complete Thursday morning.

On Friday, security forces will be blocking all roads leading to affected barangays in the cities of Tabaco, Legazpi and Ligao and the towns of Guinobatan, Camalig, Daraga, Malilipot and Sto. Domingo.

But Captain Razaleigh G. Bansawan told the Inquirer the returning residents apparently used ?backdoor? routes.

?They are familiar with the terrain. They could have used foot trails and did not take the roads which are heavily guarded,? Bansawan said.

The Joint Task Force Mayon spokesman said there were also at least 36 families who had remained in Barangays Bonga, Mabinit and Buyuan, all fronting the rolling lava. Authorities warned that they would be threatened by superheated pyroclastic materials in case of a major eruption.

Both police and military men have been instructed to conduct house-to-house checks to flush them out. Bansawan threatened to arrest any resident who was still in the danger zone on Friday.

Three-month stay

A total of 10,032 families or approximately 47,500 persons have been listed as evacuees and are likely to spend the first few months of 2010 in evacuation centers.

?We are preparing for [the villagers to spend] up to three months in the centers,? Cedric Daep, disaster relief coordinator for Albay told Agence France Presse. There are so far 29 evacuation centers, most of them schools. When school starts, government will have to find a way to accommodate both students and displaced persons, he added.

Meanwhile, the provincial government and various charities distributed special New Year?s Eve food packs to evacuees. A telecom company sponsored a concert for them.

Danger still there

Chief government volcanologist Renato Solidum warned that although Mayon appeared to be in a lull after two weeks of lava flows and ash sprays, his agency?s instruments showed a major eruption could occur any time.

?The volcano is still active. The danger is still there,? he said.

Yesterday?s bulletin from the Philippine Institute of Volcanology and Seismology (Phivolcs) said no ash explosion had been observed on Wednesday but lava continued to flow out of the volcano?s summit.

The agency said it recorded 60 volcanic earthquakes on Wednesday. There was also a total of 267 ?rock fall events,? or the detachment of lava fragments at the volcano?s upper slopes. Sulfur dioxide (SO2) emissions were recorded at an average of 1,158 tons per day.

The agency warned that the volcano ?remains inflated.?

Alert Level 4 remains hoisted, meaning a hazardous eruption is still possible ?within days.?

Phivolcs had ordered the clearing of an 8-kilometer Extended Danger Zone (EDZ) from the summit on the southern side of the volcano and 7 kilometers on the northern side.

Residents living outside these areas are also warned to be prepared to evacuate in the event of a hazardous eruption.