Manila, Oct. 29 -- A series of mild tectonic earthquakes rattled parts of Aurora province early Wednesday, with the strongest registering magnitude 4.0, the Philippine Institute of Volcanology and Seismology (PHIVOLCS) reported.

The strongest tremor, at 12:54 a.m. was located 9 km. northwest of San Luis, Aurora, at a depth of 6 km. PHIVOLCS reported Instrumental Intensity II in San Luis, Aurora, and Maddela, Quirino.

It was preceded by a magnitude 3.0 quake at 12:24 a.m., located 41 km. southeast of Baler at a depth of 3 km., which registered Instrumental Intensity I in Dingalan, Aurora.

Three subsequent tremors were recorded:

- A magnitude 3.2 quake at 2:13 a.m., 36 km. southeast of Baler.

- A magnitude 3.0 quake at 2:15 a.m., ...