A 5.3 magnitude quake shook the northern Philippines Monday but there were no immediate reports of damage or casualties.
Chief government seismologist Renato Solidum said the quake was tectonic in origin with its epicentre off the north coast of the country's main island of Luzon.
There was no sign of the quake causing a tsunami but aftershocks were expected, he said.
The civil defence office said there were no reports of damage or panic.
A 7.1-magnitude quake rocked the central Philippines on October 15, killing more than 200 people and flattening historic churches, schools and clinics.
The Philippines lies on the so-called Pacific Ring of Fire, made up of chains of islands created by volcanic eruptions that are also frequently hit by earthquakes.