The Mayon alert status was raised from 1 / abnormal to 2 / increased instability by the Phivolcs in the report of 14.01.2018 (at ... 24h30 ?). The current instability is probably of magmatic origin, a situation that could lead to more phreatic eruptions or possibly magmatic eruptions. This level is accompanied by a zone of permanent danger prohibited of 6 km radius.
The observatory said that based on seismic records, yesterday's water eruption began around 16:21 local time (a little different from that announced yesterday by the media) to end after one hour 47 minutes. Since the eruption, rock falls have been recorded intermittently, and continue.
A weak glow at the crater was observed from 10:16 pm.
Preceding this eruption, a slight inflation has been reported by the GPS network, and since October 2017, indicating the pressurization of the volcano by the rise of magma, or the disruption of its hydrothermal system.
Another phreatic eruption occurred on January 14th, beginning at 8:49 am and lasting about 5 minutes depending on the seismic data. It produced a plume of gray ash largely obscured by the cloud cover.
Update: the observatory reports an eruptive phreatic episode on 14 January at 11:43, lasting 15 minutes on the basis of seismic surveys.
Update -2 : Mayon's rise in 24 hours: after three phreatic eruptions, and 158 episodes of rock falls between January 13 at 16:21 and January 14 at 19:25, the Mayon now shows a strong incandescence related to the growth of a dome and the beginning of the lava flows on its southern flank.
As a result, the Phivolcs raised the alert level to 3, with a PDZ / permanent danger zone of 6 km radius, extended to 7 km on the southern flank.
Source: Phivolcs-DOST 14,01,2018 / 20h
The last eruption of Mayon dates back to August 12, 2014 / October 19, 2014.
Sources: various reports of Phivolcs, a little rock'n roll as to the hours mentioned.