Dhaka, Oct. 11 -- Two strong offshore earthquakes hit the same region in the southern Philippines within hours on Friday, killing at least seven people, triggering landslides, and prompting evacuations in coastal areas amid a brief tsunami alert.

The first tremor, measuring 7.4 in magnitude, struck off the coast of Manay town in Davao Oriental province, while the second, preliminary 6.8 magnitude quake, occurred later in the same area along the Philippine Trench at a depth of 37 kilometers (23 miles), according to Teresito Bacolcol, chief of the Philippine Institute of Seismology and Volcanology.

"This is a separate earthquake, which we call a doublet quake," Bacolcol told The Associated Press. "Both occurred in the same region but with...