4 lava fountains spout from Mayon on Sunday
Published: 4:28 p.m., Jan. 28, 2018 | Updated: 12:18 a.m., Jan. 29, 2018
Mount Mayon had its fourth lava fountain eruption on Sunday afternoon, the Philippine Institute of Seismology and Volcanology (Phivolcs) said.
At 3:28 p.m., the Mayon spewed molten lava, and a 2-kilometer ash plume was generated from the crater of the restive volcano.
However, officials said that they could not provide details yet on the height of the lava fountain for clouds were obscuring the view.
Despite this, Phivolcs noted that a rumbling sound was heard at Ligñon Hill when Mayon spewed lava.
READ: Phivolcs counts 3 lava fountaining on Mayon on Sunday
Earlier, Mayon had three episodes of lava fountaining.
The first incident for Sunday was at 12:45 a.m., which was followed by another at 5:36 a.m., and the third at 10:33 a.m.
The earlier lava fountain episodes were observed as incessant rain over Bicol since Friday triggered a debris flow on a stream between the Anoling river in Camalig town and Miisi river in Daraga town.
The heavy rain caused a landslide that blocked a portion of the national highway in Guinobatan, Albay province, on Sunday morning and flooded 28 villages in the nearby Camarines Sur province.
Motorists were allowed to use the single lane of the highway, while public works and highways personnel cleared the area.
All national roads and bridges in Albay were passable except for the road network at the Daang Mahalika junction of Legazpi-Tabaco-Camarines Sur and the Legazpi-Punta de Jesus road in Barangays Pawa and Tinapian in Manito town, according to the Office of Civil Defense (OCD).
At 10:33 a.m., Mayon spewed lava and ash plume for the third time on Sunday, according to the Philippine Institute of Volcanology and Seismology (Phivolcs). The lava fountain lasted 52 minutes.
During the episode, residents of Ligñon Hill, 11 kilometers southeast of the volcano, reported hearing a loud rumbling sound.
Lawrence Bañes, Phivolcs science research assistant, said the agency was not able to determine the height of the ash plume and lava fountains because of the inclement weather.
Blocked by lava
The river channels of Anoling and Miisi were supposed to serve as the path for lahar (debris flow), according to Phivolcs Director Renato Solidum.
But lava from Mayon’s eruptions blocked these channels, so that the debris flow made its way to the stream between the channels.
The debris flow was noted between 1 p.m. and 7 p.m. on Saturday.
In its advisory, Phivolcs said people should watch out for lahar or sediment-laden stream flows in other river channels besides those of Buyuan, Miisi, Basud, San Vicente, Buang, Quirangay and Masarawag-Maninila, according to Solidum.
Hot lahar, which consists of new deposits from the volcano, is usually visible due to the presence of steam, Solidum explained.
He advised residents to stay away from lahar, whether hot or cold, as this was dangerous.
Types of flows
Solidum said there were different types of lahar.
“If the solid content is 20 percent or greater, we can call that lahar,” Solidum said.
He said water with less than 20 percent lahar was considered a flood or stream flow.
A flow with 20 to 60 percent solid content is hyperconcentrated lahar, or thin lahar, he explained.
If the flow consists of more than 60 percent solid, it is called thick lahar, which Solidum describes as like concrete.
“If there is so much sediment, the lahar will push the boulders in front,” he said.
When boulders collide with those blocking their way, a sound is produced, signaling that lahar is approaching.
“This (Sunday) morning, there was hyperconcentrated stream flow … in the same stream,” Solidum said.
High possibility of lahar
He said it would take only 40 millimeters of sustained, heavy rain for an hour and a half for lahar to occur.
With Albay currently experiencing scattered rainshowers, he said there was a very high possibility of lahar.
Even if a river channel has volcanic deposits, rainwater may still plow the old deposits, according to Solidum.
“Ideally, where there are new deposits, you expect lahar, but people should understand that the slopes of Mayon volcano is covered with loose sand, ash, or rocks that can be remobilized even though they are old,” he said.
In Camarines Sur, villages in Garchitorena, Lagonoy and Buhi towns, and Iriga City were flooded due to swollen spillways and river channels, the OCD regional director, Claudio Yucot, reported to the National Disaster Risk Reduction and Management Council.
The local government of Taguig City, meanwhile, has extended P3 million in assistance, including 3,000 relief packs consisting of hygiene kits, face masks, and rice and canned goods, to Albay residents affected by Mayon’s restiveness. –With reports from Rey Anthony Ostria, Mar S. Arguelles and Michael Jaucian, Inquirer Southern Luzon; and Dexter Cabalza in Manila
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