The Philippine Institute of Volcanology and Seismology (Phivolcs) warned on Monday that a volcanic tsunami might happen if the Taal Volcano alert level is raised to 5, which is the highest alert level, according to Inquirer.net.

Alert level 5 also means that a violent volcanic eruption that could affect a large area is already underway, according to The Guardian. To prevent injuries in case the volcano erupts, people need to be evacuated from high-risk zones ahead of time, Phivolcs head Renato Solidum explained.

At the moment, Phivolcs raised the Alert Level of Taal Volcano to 4. This basically means that an explosion may happen within hours or days.

But Filipinos who live near the Taal Lakeshore are encouraged to already evacuate as early as possible. “A volcanic tsunami is possible if Taal’s activity further intensifies to level 5,” Phivolcs Supervising Science Research Specialist Winchelle Sevilla said. “If there are residents near the lakeshore area, they should be evacuated since it’s possible for a volcanic tsunami to occur should Taal’s activities further heighten.”

Taal Volcano erupted on Monday sending a column of ash and small rocks into the air as red-hot lava was seen flowing from it. The eruption triggered the evacuation of around 8,000 people from the affected area, BBC reported.

There were no reported casualties after Monday’s incident. However, ash reached as far as Manila located around 100 kilometers from the volcano forcing its international airport to shut down. Offices and schools are closed as well. The country’s main airport, which handles more than 240 flights daily, was later reopened on Monday.

Local officials said that they encountered some problems with the evacuation. There were people who can’t be moved out immediately due to the lack of transport as well as the poor visibility in the affected areas due to the ash.

Other residents, however, refused to leave their homes while some of those who already left tried to reenter the danger zone. “We have a problem, our people are panicking due to the volcano because they want to save their livelihood, their pigs and herds of cows,” Wilson Maralit, the mayor of Balete, told DZMM radio. ”We’re trying to stop them from returning and warning that the volcano can explode again any time and hit them.”

Taal is one of the many active volcanoes in the Philippines, which sits in what is known as the Ring of Fire, a zone with active seismic activity in the Pacific. The volcano erupted more than 30 times in the past 500 years. It’s 1911 eruption claimed the lives of 1,500 people