Earlier, officials asked some 45,000 people who fled the volcano’s wrath to return home to ease overcrowding in evacuation centers and reduce the risk of epidemics.
Health department officials said hundreds of people have been stricken with respiratory illnesses in government centers as the volcano’s eruption continued for the seventh day.
Health Secretary Manuel Dayrit said the risks of diarrhea and lung infections were the biggest threats to the evacuees because of inadequate clean water and sanitation facilities at the centers.
Experts said it is possible the two explosions, which occurred at 4:05 and 5:02 p.m., were part of an isolated volcanic activity.
Volcanologist Eduardo Laguerte said people with homes beyond six kilometers of the crater "may be allowed to go home" despite the threat of more hazardous eruptions.
Laguerte said volcanologists have concluded that only three barangays  Ma-binit, Bonga and Buyuan  were in immediate danger from the volcano.
But the flows from yesterday’s explosions apparently stopped at the base of the volcano with no damage immediately reported to nearby barangays, where residents were trying to resume normal lives.
Volcanologist Ed Villacorte warned yesterday the massive volcano’s last blast may force the evacuation of 41,000 people from 18 barangays as the designated danger zone widens.
Villacorte said the so-called pyroclastic flows can move at up to 100 kilometers per hour with temperatures up to 700 degrees Celsius.
Villacorte said the six-month rainy season has just begun, and the water is swelling new ash deposits into steaming batches of mud, perched precariously on the mountainside above several small settled areas.
Mayon has coughed up five million cubic meters of ash and dry rock fragments in the past six days and most of it has settled in the volcano and could fall over the coming days or months, he added.
In an advisory yesterday, the Philippine Institute for Volcanology and Seismology (Philvolcs) said Mayon’s edifice remains inflated as indicated by ground deformation measurements using electronic distance meter and electronic tiltmeters.
"The status of Mayon Volcano remains at Alert level 5," read the advisory. "Based on the volcano monitoring parameters and visual observations, explosive eruptions are still possible in the following days."
Philvolcs warned the public to keep away from the six-kilometer permanent danger zone and eight-kilometer extended danger zone in the southeast portion of Mayon.
"Secondly, pyroclastic flows, rockfalls and ash fallout can occur any time due to the unstable volcanic materials deposited on steep ground," read the advisory. "If heavy rains occur over the volcano, the public should avoid going near river channels around Mayon because of potential lahar flows."
The number of evacuees fleeing Mayon’s eruption has risen to 44,249 as of yesterday based on the tabulation of the provincial Social Welfare and Development Office.
Two new evacuation centers have also been opened at the Amtic Elementary School in Ligao City and at Bariw Elementary School inside the FVR resettlement area in Camalig town for some 257 families.
Dr. Veronica Madulid, provincial health officer, said at least 276 children at the Central School and San Jose evacuation centers in Malilipot town have been immunized against measles.
Madulid said the immunization drive was necessary to stave off the threat of infectious diseases after measles was detected in a child in an evacuation center.
Madulid said a medical team led by Dr. Pablo Filip Jr. arrived at the San Jose evacuation yesterday to provide medical services to the evacuees.
Madulid said 246 evacuees are suffering from acute respiratory infection; followed by headache, 42; traumatic injuries, 22; skin diseases, 22; allergy, 17; and 14 people with diarrhea at 14.
Of the 13,021 evacuees in Bagumbayan, Bogtong, Taysan, Cabaugan, and Albay Central School; 42 are suffering from cough and colds; colds with fever, 41; fever, 32; and 25 with headache, she added.
Gov. Al Francis Bichara has ordered the distribution of seven US-made tents to various evacuation centers in Legazpi City and three in the towns of Malilipot and Sto. Domingo. – With reports from Felix delos Santos