MANILA, April 9 (Xinhua) -- Filipino scientists are paying closer attention to Bulusan Volcano in Sorsogon in central Philippines after two explosions of the volcano were reported Sunday and Monday, the Philippine Institute of Volcanology and Seismology (Phivolcs) said Monday.

    Phivolcs has re-deployed one of the instruments from neighboring Mayon Volcano Observatory in Albay to Sorsogon station for Mt. Bulusan watch.

    The institute said Monday's seismic event was recorded by the seismographs around Bulusan Volcano for about 20 minutes and villagers living nearby heard rumbling sounds coming from the volcano.

    Alert Level 1 has remained in effect over Bulusan Volcano and the public is thereby reminded not to venture into the four-kilometer radius Permanent Danger Zone (PDZ) because the area is at risk of sudden steam or ash explosions, said Phivolcs.

    Residents near river channels have also been warned against life-threatening lahar flows from the volcano as ash and other loose volcanic materials might be remobilized under bad weather conditions such as heavy wind and rainfall.

    Mudslides from Mayon Volcano buried alive hundreds of villagers living at the food of the mountain when super typhoon "Durian" hit central Philippines in November last year.