A 6.3-magnitude earthquake struck off the coast of Hualien at 7:35 a.m. on Friday. The quake was extremely shallow, and could be felt throughout the island of Taiwan at lesser magnitudes of 4 in Hualien, Yilan, Nantou, and Tainan counties, and 3 as far as New Taipei, Taoyuan, Chiayi, and Kaohsiung cities. The Central Weather Administration (CWA) elaborated that Friday morning’s quake is believed to be an independent event.

CWA Seismological Center Deputy Director Hsu Li-Wen (許麗文) said that the earthquake was caused by a subduction event between the Philippine Sea Plate and Eurasian Continental plate, and was likely not related to the 0403 quake. The quake is also believed to be unrelated to the 5.7-magnitude quake that struck off the coast of Yilan on Thursday, caused by a similar subduction. That said, Hsu suggested locals in the area to be cautious, as it’s possible the area could experience aftershocks with magnitudes of up to 5.5 anytime within the next three days.

Friday morning’s earthquake was felt all across Taiwan, with national alerts sent out to 15 counties, including Kaohsiung, Pingtung, and Keelung. Residents in Taipei were also sent an alert, despite only feeling the quake at a magnitude 2, due to the basin effect and the effect of high-rise buildings.

Hsu said eastern Taiwan experiences frequent seismic activity, yet predicting the exact time and locations of major quakes remains far-fetched for scientists across the world.