Taiwan Semiconductor Manufacturing Co. evacuated factories following a 6.4 magnitude earthquake near the city of Chiayi that injured at least four people and suspended work at factories across the island’s south.

Chipmaker TSMC said on Tuesday that all its sites were operating following an overnight 6.4 magnitude earthquake in southern Taiwan that was centred on a mountainous rural area and caused only minor damage and light injuries.

A 6.4-magnitude earthquake struck a mountainous, rural area of Taiwan’s south on Jan 21, the island’s weather administration said, injuring 27 people and causing ceilings of homes to cave in according to the local authorities. The quake had a depth of 9.4km with its epicentre in Dapu township in Chiayi county, the weather administration said.