The state seismologists on Wednesday said it has monitored continuous "repetitive pulse tremor" in Mayon Volcano in Albay province.
In its latest bulletin, Phivolcs said the pulse tremor is still ongoing since it was first observed at 3:47 PM on July 3.
The state seismologist also logged 232 rockfalls events and 1 volcanic earthquake from 5 AM on July 4 to 5 AM on July 5.
The total number of rockfalls is lower than the 397 rockfalls observed on July 2.
The Mayon Volcano also exhibited 5 dome-collapse pyroclastic density currents (PDCs) that had 2 to 2.5 minutes duration. No lava-front PDC have been reported.
The sulfur dioxide emission had a slight decrease, from previous 1,558 to 1,170.
A 200-meter long steam-laden plumes, generated from the continuous moderate degassing, were also seen.
Meanwhile, the lava flowing down the Mi-si Gully maintained its length of 2,800 meters from the summit's crater while 1,300 meters on Bonga Gully.
"[C]ollapse debris has deposited to four thousand (4000) meters from the crater," the state seismologist said.
Phivolcs said both its short-term observations and longer-term ground deformation parameters showed that the Mayon Volcano's edifice has signs of inflation.
Alert Level is still hoisted over Mayon Volcano.
Meanwhile, interviewed by Philippine Information Agency (PIA) Bicol Region, Phivolcs Volcanologist Paul Karson Alanis explained that the repetitive pulse tremor could be attributed to the "fluid gas that moves inside the magma chamber."
"Sa tingin namin, itong bubbles na ito ay unti-unting umaakyat mula sa ilalim at namumuo. Binabantayan natin kasi baka ito ang simula ng build-up ng pressure ng Mayon Volcano which may lead to explosive erruption," he added.
