Taal is still a big threat to erupt

Volcano experts in the Philippines are monitoring the Taal volcano closely for signs of a major eruption. At press time, the volcano’s activity has eased since it began spewing steam and ash two weeks ago, but the threat of a large-scale eruption remains, say scientists. In addition to the immediate risk to life, such an event could contaminate water supplies and disrupt power generation for millions of people, and halt ground and air travel.

At 2:30pm local time on Jan. 12, Taal — which is on an island about 60 kilometres south of Manila — started ejecting lava and blew a giant plume of rock fragments, known as tephra, up to 15 kilometres high. Ash travelled as far north as Quezon City, some 70 kilometres away, forcing tens of thousands of people living on Taal’s Volcano Island and in nearby provinces to evacuate.

The volcano’s activity has stalled, but this does not mean the worst is over, said volcanologist Mariton Bornas, who heads the division responsible for monitoring and predicting eruptions at the Philippine Institute of Volcanology and Seismology, a government agency in Quezon City, just north of Manila.

The volcano remains at level 4, the second-highest level on the country’s volcano-alert system, which means a hazardous eruption could happen any time. Scientists say the threat of a major eruption remains high because analysts have reported hundreds of volcanic earthquakes, as well as the emergence of fissures, and receding of the surrounding lake. The ongoing seismic activity suggests that magma is continuing to rise to the volcano's surface from deep within the Earth. Since the sixteenth century, Taal has erupted about 30 times, including four major events.