Phivolcs Director Teresito Bacolcol told INQUIRER.net on Friday that it was the Mayon and Bulusan Volcano observatories that noticed the volcanic haze in the region through its visual monitors.

One of the country’s most active volcanoes, Bulusan has been showing signs of unrest with on-and-off ash and steam explosions in recent years. “It is currently in an abnormal condition,” the ...