MANILA, Philippines - Rains prevented the Philippine Institute of Volcanology and Seismology's (Phivolcs) from closely monitoring all the activities of the restive Mayon Volcano, the agency said Tuesday.
In its 7 a.m. Tuesday report, the Phivolcs said its monitoring team in Albay province failed to measure Mayon's sulfur dioxide emission due to rains "that covered over the volcano area."
It also failed to monitor the volcano's steaming activity and the crater glow because Mayon's summit was covered by thick clouds the whole time on Monday.
The bulletin said 3 volcanic earthquakes were detected from Mayon. The Phivolcs also counted 21 rockfall events related to the detachment of lava fragments from the volcano's upper slopes.
The Phivolcs on Saturday lowered the alert level hoisted around Mayon Volcano from 4 to 3 after the volcano's activity calmed down late December.
The lowered alert level prompted the local government to bring back more 7,000 families to their homes located within the 7-kilometer to 8-kilometer extended danger zones of the volcano.
Meanwhile, the Phivolcs said that the 7-kilometer extended danger zone on the southeast flank of the volcano should “be free from human activity" due to possible sudden explosions from the volcano.
"People residing close to these danger areas are also advised to observe precautions associated with post-eruption activity, such as rockfalls, pyroclastic flows, and ash fallout which can also occur anytime due to instabilities of lava deposited on steep slopes," the Phivolcs said.
The Phivolcs also advised people to avoid "lahar prone" river channels in the southern sector of the volcano during bad weather conditions.
Several residents who have been allowed to return home have expressed fear over deadly mud slides from the volcano.