Thursday, January 25, 2018

RUMBLINGS AND SUBTERRANEAN NOISE CONTINUES AS MAYON VOLCANO EJECTS LAVA AND INCANDESCENT STONES



LEGAZPI CITY (Jan 25) – The subterranean rumblings already felt every now and then with intensity and produced some terrestrial commotions over Mayon Volcano which caught the attention of the people and began to be fearful and worried.

This resulted to the rise of the number of evacuees fleeing the Mayon Volcano eruption to 19,407 families or 74,224 individuals after the Provincial Disaster Risk Reduction and Management Council (PDRRMC) extended the danger zone 8-kilometers and 9-kilometers buffer zone.

In its 8:00AM Bulletin Thursday, Philippine Institute of Volcanology and Seismology (PHIVOLCS) recorded six (6) episodes of intense but sporadic lava fountaining from the summit crater lasting nine (9) minutes to fifty-eight (58) minutes. The lava fountains reached 400 meters to 500 meters high and generated ash plumes that reached 3 kilometers to 5 kilometers above the crater, between 06:02 AM yesterday to 03:00 AM this morning.

The events fed lava flows on the Mi-isi and Bonga Gullies, sprayed near-vent lava spatter, and fed incandescent rockfall on the summit area. Pyroclastic density currents or PDCs on gullies heading the Mi-isi, Lidong/Basud, and Buyuan Channels were also observed. The runout of PDCs on the Buyuan Channel is now exceeding 5 kilometers from the summit crater.

Alert Level 4 remains in effect over Mayon Volcano. The public is strongly advised to be vigilant and desist from entering the eight (8) kilometer-radius danger zone, and to be additionally vigilant against pyroclastic density currents, lahars and sediment-laden streamflows along channels draining the edifice.

A total of thirteen (13) tremor events, six (6) of which correspond to the lava fountaining events, two (2) episodes of pyroclastic density current or PDC generation from lava collapse, and numerous rockfall events were recorded by Mayon's seismic monitoring network. Rockfall events were generated by the collapsing lava front and margins of the advancing lava flow on the Mi-isi Gully and by shedding from the summit dome onto the Bonga Gully. Currently, the Mi-isi and Buyuan lava flows have advanced to three (3) kilometers and one (1) kilometer, respectively, from the summit crater. Sulfur dioxide gas emission was measured at an average of 1252 tonnes/day on 24 January 2018. Electronic tilt and continuous GPS measurements indicate a sustained swelling or inflation of the edifice since November and October 2017, consistent with pressurization by magmatic intrusion. PHIVOLCS maintains close monitoring of Mayon Volcano said Paul Alanis – PHIVOLCS Science Research Specialist. (Mar de la Cruz)

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