The Philippine Institute of Volcanology and Seismology has recorded 1,583 aftershocks after the Magnitude 7.4 earthquake in Surigao del Sur last Saturday.

• Major aftershocks jolt Mindanao after magnitude 7.4 quake

Phivolcs chief Teresito Bacolcol said the November 17 quake in Sarangani is not connected to the December 2 earthquake in Surigao del Sur, saying different earthquake generators are responsible for the temblors.

"We have 6 active trenches and we have 175 active faults, so there is always a probability na pwedeng magkasabay," he said.

He also warned that a similar magnitude 7.2 earthquake coming from the West Valley Fault could leave 33,000 casualties in Metro Manila.