MANILA, Philippines – More than 1,200 aftershocks have been recorded by the Philippine Institute of Volcanology and Seismology (Phivolcs) following the magnitude 6.9 earthquake that hit Negros Oriental and Cebu.

Phivolcs said 1,239 aftershocks have been recorded as of Wednesday afternoon, 69 of which were felt by people.

The strongest aftershock on Wednesday was felt at 8 a.m. It measured magnitude 5.2 in Guimaras and Tayasan.

However, Phivolcs noted that the aftershocks are now getting weaker.

State geologists are now studying the fault line where the main quake occurred.

Initial investigations showed that the fault is 10 kilometers deep and is up to 50 kilometers long.

This particular type of fault is capable of generating strong earthquakes, but not as strong as quakes generated by major faults mapped across the country, which usually reach up to 100 kilometers in length, Phivolcs said.

The new fault is located between the islands of Negros and Cebu and is relatively harder to plot since it is located along Tanon strait.

Active faults

More than 40 active faults in the country have been mapped by Phivolcs.

A suspected fault line cuts across Negros Oriental and another one is found in Cebu.

According to Phivolcs, they were unable to plot the fault that caused the 6.9-magnitude quake last Monday because no previous earthquakes have been recorded in the area.

Seismologist Dr. Winchelle Sevilla said some faults take a long time before they show any activity.

These faults are considered more dangerous because they are capable of producing stronger quakes.

Phivolcs want to accurately plot the new fault to prevent the building of infrastructure in the area. -- Report from Zen Hernandez, ABS-CBN News