Earthquakes monitored by Mt. Kanlaon’s seismic monitoring network have considerably decreased since June 22, when two magnitude 4.7 tremors rocked areas surrounding the volcano on Negros Island.

As of 8 a.m. on Thursday, the Philippine Institute of Volcanology and Seismology’s (Phivolcs) Kanlaon Volcano Bulletin reported that only six volcano-tectonic earthquakes on the western flanks were recorded during the 24-hour observation period.

The number is remarkably lower than the 136 and 104 earthquakes recorded on June 22 and 23, respectively.

Mari-Andylene Quintia, a science research specialist at the Kanlaon Volcano Observatory based in La Carlota City, Negros Occidental, said the two earthquake events on June 22 are “considered the mainshocks and the rest are aftershocks.”

“Aftershocks are expected to be of less magnitude than the mainshock, but could last for several days to several months depending on how big the energy was released,” Quintia told the Philippine News Agency (PNA) in an online interview.

She reiterated that entry into the four-kilometer radius permanent danger zone (PDZ) is still prohibited.

“We are continuously monitoring the Kanlaon Volcano activity. Any changes would be relayed to all concerned immediately,” Quintia said.

Mt. Kanlaon remains at Alert Level 1, which means the volcano is at an abnormal condition and has entered a period of unrest.

Localities near the volcano were alerted following the two earthquakes on June 22.

The epicenter was between Bago City and La Carlota City, prompting the two cities to step up disaster preparedness.

On June 23, a total of 76 residents of Barangay Ilijan in Bago were evacuated after earthquakes were felt, and sulfuric fumes were emitted by the volcano in the area.

The Bago City Disaster Risk Reduction and Management Office has been conducting information, education, and communication campaign and assessment as part of its preparedness activities.

In La Carlota, the City Disaster Risk Reduction and Management Council has set up a command center, activated the city’s incident command system, and mobilized the Barangay Disaster Risk Reduction and Management Councils. (PNA)