TAIPEI (Taiwan News) – A magnitude 6.4 earthquake struck east of Taiwan Wednesday at 7 p.m., triggering a national alert, the Central Weather Administration said.

The quake struck 69.9 kilometers south of Hualien County Hall, under the Pacific Ocean close to the coast, at a focal depth of 30.9 kilometers.

The quake’s biggest intensity level reached a low level 5 in Taitung County, and level 4 in Hualien, Nantou, Taichung, Changhua, Miaoli, Yunlin, and Chiayi County. Taiwan uses an intensity scale of 1 to 7, which gauges the degree to which a quake is felt at a specific location.

No damage was immediately reported after the tremor, but mass rapid transit rail systems in the Taipei area had their trains reduce speed. High-speed rail services between Taipei and Kaohsiung were not affected.

The Central Weather Administration warned that aftershocks of magnitude 5 to 5.5 might be possible within the next three days, per CNA.