MANILA (2nd UPDATE) - Taal Volcano spewed more ash on Friday morning, proof that magma continued to churn beneath its volcano's surface, state seismologists said.

The ash emission, which started at 5:11 a.m. was the "strongest in the past few days," Taal resident volcanologist Paolo Reniva said.

Taal has a 30-percent chance of a hazardous eruption and residents should stay out of danger zones, especially the volcano island where steam-driven or phreatic eruptions could occur, said Phivolcs officer-in-charge Renato Solidum.

"Ito ay patunay na may aktibidad pa sa ilalim kasi nandyan pa po ang magma at 'yung tubig diyan ay napapakuluan. Wala lang masyadong puwersa para magkaroon ng pagsabog pero 'yung steaming eh nag-increase nang konti," Phivolcs officer-in-charge Renato Solidum told radio DZMM.

(This is proof that there's still activity underneath, the magma is still there and the water is being heated. There just isn't enough force to cause an eruption but the steaming increased.)

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"Pag nabara 'yung usok na 'yan, s'yempre magkakaroon ng pressure. Baka sumabog," he said.

(If the steam is trapped, there will be pressure. It may erupt.)

"'Yung 3 out of 10 chances or 30 percent, mataas po yun. Kung ang pag-uusapan ay mas maliit na pagsabog, mas mataas pa po ang tiyansa."

(Three out of 10 chances of 30 percent is high. If we're talking about smaller eruptions, the chances are higher.)

The volcano remains under alert level 4, the second-highest in a 5-step warning system, meaning a "hazardous explosive eruption is possible within hours to days," according to Phivolcs.

Taal's ash eruption last Jan. 12 displaced nearly 148,000 people and damaged at least P3.2 billion worth of crops and livestock, authorities said.

Towns and cities under lockdown could change as authorities identify areas in danger of base surge, or volcanic particles that rush down from volcano's slopes, said Col. Edwin Quilates, Batangas provincial police chief.

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"Magre-readjust po kami ng control points at lockdown area," Quilates told radio DZMM.

(We will readjust our control points and lockdown area.)

"Maaaring magbago ang terminology natin ngayong araw. Maaaring bitawan na natin yung terminology na 14-km danger zone. Baka gamitin na natin yung base surge dun sa mapping ng Phivolcs."

(We may switch our terminology today to Phivolcs' mapping of base surge instead of the 14-km danger zone.)

In the past 24 hours, the volcano's main crater emitted plumes of steam as far as 500 meters in the air and sulfur dioxide measured at 224 tons.

Some 738 volcanic earthquakes were plotted in the Taal region since Jan. 12, data from the Philippine Seismic Network (PSN) showed. Among these, some 176 were felt, ranging from between Magnitude 1.2 and 4.1 and experienced at between Intensity 1 and 5.

The Taal Volcano Network, which can record small earthquakes undetectable by the PSN, recorded 486 volcanic earthquakes in the past 24 hours.