MANILA — Tens of thousands who fled from the eruption of Taal Volcano a week ago should stay put in evacuation centers as another "hazardous explosive eruption" remained possible, the state seismology institute said Sunday.

In the past 24 hours, Taal unleashed "steady steam emission and infrequent weak explosions" that generated 500 to 1,000-meter-tall ash plumes, Phivolcs said in an 8 a.m. bulletin.

Set in the center of a picturesque lake south of the capital, the volcano in the last 24 hours also spawned 787 quakes, of which only 1 was felt at a "scarcely perceptible" intensity 1, said Phivolcs.

This "intense" seismic activity likely signifies that magma continues moving towards the volcano's crater, it warned.

The second-highest alert in a 5-step system remains hoisted over Taal, which means "hazardous explosive eruption is possible within hours to days," Phivolcs added.

Residents who were moved away from the volcano island, its lake and the connected Pansipit River, and areas around Taal's 14-kilometer radius should stay in evacuation centers, Phivolcs volcano monitoring division chief Mariton Bornas told reporters.

"You have ash dispersed around the volcano, sometimes mayroong mga minor [lava] flows na bumababa ng bibig sa bulkan, then mayroon of course malakas na expulsion ng gas. Napakapanganib ng mga ito," she said.

(Sometimes there are minor lava flows from the volcano's crater, then there is of course strong gas expulsion. These are very dangerous.)

'FASTER' UNREST

Taal last Jan. 12 belched a giant ash cloud that reached Metro Manila, temporarily suspended operations at the capital's main airport and damaged at least P3 billion worth of crops and livestock.

If the volcano erupts again, it could show a "faster progression" of seismic events, said Bornas.

"Open na iyong bulkan. Mas madali pong makasampa ang magma, wala nang pumipigil sa kaniya na pressure. Kung ano man iyong nakabara noong una e natanggal na," she explained.

(The volcano is already open. The magma will climb up faster because there is no longer any pressure preventing it from doing so. Whatever was blocking it before had been removed.)

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4-HOUR WINDOW

Some local governments allow residents to check on their abandoned homes during certain "window hours."

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"We stand firm on recommendation natin: dapat po totally evacuated at dapat po hindi pumapasok sa naka-define na danger zone," said Phivolcs' Bornas.

(We stand firm on our recommendation that the danger zone should be totally evacuated and no one should enter it.)

Bornas, however, conceded that Phivolcs considered scientific data, while local governments also take into account the concerns of their constituents and economic implications.

Taal, one of the most active volcanoes in the Philippines, has erupted more than 30 times in the past 5 centuries, most recently in 1977. An eruption in 1911 killed 1,500 people and one in 1754 lasted for a few months. -- With a report from Reuters

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