MANILA, Philippines - Mount Bulusan on Friday morning spewed ash and steam anew, the fourth time since Alert Level 1 was raised on the volcano last week.

The Philippine Institute of Volcanology and Seismology (Phivolcs) said the ash explosion occurred at 6:59 a.m.

It said that the explosion produced an ash and steam cloud which rose to about 700 meters above the volcano's summit. Most of the ash was carried to

Before the explosion, 4 volcanic earthquakes were detected from the volcano and weak steaming was observed from the crater.

A report by ABS-CBN correspondent Jeff Canoy said most of the ash is drifting towards Casiguran village in Escuala. He said the weather near the volcano remains clear unlike during the weekend when rain turned the ash into mud.

Some residents have also complained that the ash fall could trigger respiratory problems, which prompted many to wear gas masks.

Alert Level 1 was raised on Bulusan volcano after it emitted ash and steam over the weekend.

Despite the ash explosion, residents within the 4-kilometer permanent danger zone refuse to leave their homes.

Health officials have been visiting residents everyday to check on their conditions.

Local officials are also closely monitoring areas that may be affected by possible lahar flow from the volcano.

The Phivolcs has repeatedly warned residents against possible lahar flows during heavy and continuous rainfall. With a report from Jeff Canoy, ABS-CBN News