Manila, March 12 -- Lava effusion is a normal occurrence in active volcanoes, but communities should watch for lava flows, the head of the Philippine Institute of Volcanology and Seismology (Phivolcs) said Thursday.

The Phivolcs captured a two-minute lava effusion at Mayon Volcano on Thursday, which generated an ash plume that reached 700 meters high.

"Lava effusion happens when magma reaches the surface and releases pressure gradually. It is usually less explosive," Phivolcs Director Teresito Bacolcol told the Philippine News Agency in an interview.

He explained that lava effusion does not automatically produce an ash plume, but it can still produce small ash emissions and is normal for many active volcanoes.

Lava effusion is the pro...