Central Weather Administration Seismological Centre section chief Chen Da-yi told a late-night press conference that the earthquake was caused by the “northward subduction of the Philippine Sea Plate colliding with the Eurasian Plate”.

Or, in layman’s terms, one of the tectonic plates slid under the other and caused fiction in the form of an earthquake. 

Chen said it was a similar geological phenomenon seen earlier this year when as magnitude 6.1 earthquake struck off the coast of Yilan on August 27.

“Saturday’s quake was felt across Taiwan, but because it occurred at a considerable depth and its epicentre was offshore, it was relatively unlikely to cause serious damage,” he said, according to local media reports. 

Chen added that a national-level earthquake alert was issued 15.2 seconds after the quake, covering nearly all counties and cities in Taiwan. A second alert followed 16.3 seconds later, targeting Pingtung County and outlying islands.

He urged the public to remain vigilant for aftershocks that may reach magnitudes of 5.5 to 6 throughout the next week.