Manila, July 8 -- While communities around the Taal Volcano must stay vigilant, the head of the Philippine Institute of Volcanology and Seismology (Phivolcs) said Tuesday they have nothing to worry about.

"They just have to stay vigilant and refrain from entering the permanent danger zone which is the whole Taal Volcano Island," Phivolcs Director Teresito Bacolcol told the Philippine News Agency in an interview.

Based on the 24-hour observation from 12 a.m. Monday to 12 a.m. Tuesday, there is an ongoing volcanic tremor in Taal since 3:37 a.m. Sunday.

Bacolcol said continuous volcanic tremor may last for several days.

"There were instances in the past when Taal Volcano had volcanic tremor for several days," he added.

Volcanic tremor, ...