The Philippine Institute of Volcanology and Seismology (Phivolcs) said Monday, October 30, that Mayon Volcano remains on alert level 1 following the occurrence of at least 57 volcanic quakes since Saturday, indicating its sustained abnormal state.
Alert Level 1 means Mount Mayon is having an "abnormal condition."
"Although this means that presently no magmatic eruption is imminent, it is strongly advised that the public refrain from entering the 6-kilometer radius Permanent Danger Zone due to the perennial life-threatening dangers of rockfalls, landslides/avalanches at the middle to upper slope, sudden ash puffs and steam-driven or phreatic eruptions from the summit," the Phivolcs 8 a.m. bulletin stated.
Phivolcs resident volcanologist Ed Laguerta said the agency is closely monitoring the surge of volcanic earthquakes currently taking place for the past three days, specifically the parameters that could trigger the volcanic tremors.
When asked on the possible reasons for the tremors, Laguerta said these are due to "rock fracturing" due to pressure beneath the volcano's edifice.
Laguerta said they are currently assessing the state of the volcano based on given parameters.
"So far, there is still no indication that Mayon's abnormal behavior has intensified," he said.
Laguerta added the parameters for an abnormal state of a volcano include: gas quakes (volcanic, harmonic) gas emission, edifice inflation, magma intrusion, and crater glow.
Seismic monitoring instruments recorded series of volcanic quakes on Saturday with 32 quakes, Sunday - 12, and Monday with 13 quakes, he added, during a phone interview.
Instruments also observed moderate emission of white steam-laden plumes during the past 24-hour observation period, while sulfur dioxide emission was measured at an average of 441 tons per day during the past three days.
GPS and Tiltmeter measurements also indicate the continuous inflationary trend on the volcano's edifice.
Meanwhile, Cedric Daep, executive director of the Albay Public Safety Emergency and Management Office (Apsemo), said Monday that they are reiterating their pre-disaster advisory to residents and visitors to refrain from entering the six-kilometer radius Permanent Danger Zone due to sudden rockfalls, landslides, avalanches including ash puffs and steam-driven or phreatic eruptions from the volcano's summit.
He also warned villagers living along river channels and lahar prone areas surrounding the volcano to be on alert for possible flooding and lahar flows in times of prolonged heavy rains.
Daep stressed the importance of having an updated listing of the affected population in the danger zones in order for Apsemo to be prepared to undertake proper evacuation procedures when the need arises.
The 2,460-meter high Mayon Volcano last erupted on September 18, 2014.
La Palma was rocked by more than 40 seismic movements of low magnitude and intensity between 1.5 and 2.7 on the Richter scale, according to the data of the National Geographic Institute.
The biggest earthquake, recorded at around 1pm on Saturday, had a magnitude of 2.7 and took place in the area of the Natural Park Cumbre Vieja, 28 kilometres deep.
The second largest quake, of 2.6, took place at 1.23pm on Sunday in the same area, while the third quake erupted at midnight on Monday, reaching a magnitude of 2.1, according to the Volcanological Institute of the Canary Islands (Involcan).
The earthquakes have sparked panic across the Canary Islands, with volcano experts pulled in to examine the unusual seismic activity.
María José Blanco, director of the National Geographic Institute in the Canary Islands, said the island has "never recorded a similar swarm" and although the energy levels are low and very deep, it is different from the seismic activity they have recorded so far.
The Ministry of Territorial Policy, Sustainability and Security of the Government of the Canary Islands, respecting the Special Plan for Civil Protection and Emergency Care for Volcanic Hazards, will meet with the Scientific Committee of Evaluation and Monitoring of Volcanic Phenomena, to evaluate the data obtained from monitoring stations on the island.
A scientific team of five will also visit La Palma to keep track of the tremors in situ.
Ms Blanco said the team will start to increase the number of seismic stations in the volcanic monitoring network in a bid to develop the geochemical measurements usually carried out in the island of La Palma.
So far, the earthquakes have not been felt by residents because they are occurring at a great depth.
The last significant seismic activity in the archipelago took place in 2011 on the island of El Hierro, which finally led to the eruption of an underwater volcano in the southeast of the island.
The eruption was followed by more than 7,500 earthquakes, which lasted for three months.
La Palma is a volcanic ocean island, which rises almost 7km above the floor of the Atlantic Ocean. There is road access from sea level to the summit at 2,426metres, which is marked by rocks called Los Muchachos.
A scientific team will visit La Palma to keep track on the tremors
It was originally formed as a seamount through submarine volcanic activity and is currently, along with Tenerife, the most volcanically active of the Canary Islands.
The island is composed of two large volcanic centres.
The northern part of La Palma is dominated by the older Taburiente, with a width of 9 km and a depth of 1,500 metres and is surrounded by a ring of mountains ranging from 1,600m to 2,400m in height.
Around a half a million years ago, the Taburiente volcano collapsed with a giant landslide, forming the Caldera de Taburiente.
But the younger 1949-metre-high Cumbre Vieja, the southern volcano, is one of the most active in the Canaries.