Saturday's quake 2nd strongest since 1999; aftershocks warned

Taipei, Dec. 28 (CNA) A magnitude 7.0 earthquake struck Taiwan late Saturday, the strongest since the 7.3 Nantou quake in 1999 and last year's 7.2 Hualien quake, with authorities warning of possible aftershocks of magnitude 5.5-6.0 over the next week.

According to the Central Weather Administration (CWA), Saturday's quake was the strongest to exceed magnitude 7 since the 1999 earthquake that occurred in Jiji, Nantou County on Sept. 21, and last year's 7.2 Hualien earthquake on April 3.

The magnitude 7.0 earthquake jolted Taiwan at 11:05 p.m., with its epicenter offshore about 32.3 kilometers east of Yilan County Hall at a depth of 72.8 km, shaking 17 cities north of Tainan and eastern counties, where it reached intensity level 4 on Taiwan's seven-tier scale.

"Saturday's quake was strongly felt across Taiwan, but because it occurred at a considerable depth and its epicenter was offshore, it was relatively unlikely to cause serious damage," Chen Da-yi (陳達毅), a section chief at the CWA's Seismological Center, said at a late night press conference.

In Hualien, the shaking lasted 21 seconds, while in Taipei, New Taipei, Hsinchu, Taoyuan, and Miaoli it lasted around 10 seconds, Chen said.

The 1999 earthquake killed more than 2,400 people, injured thousands, and caused widespread destruction in central Taiwan. The Hualien earthquake left 20 dead and over 1,000 injured.

As of 2 a.m. Sunday, authorities have reported no major injuries from the earthquake.

The earthquake resulted from the northward subduction of the Philippine Sea Plate beneath the Eurasian Plate, releasing energy at a depth of 72 kilometers--a mechanism similar to the 6.1-magnitude earthquake that occurred offshore Yilan on Aug. 27, Chen said.

Wu Chien-fu (吳健富), director of the CWA's Seismological Center, said that the late-night quiet, combined with the effects of tall buildings and the Taipei Basin, made the shaking feel especially pronounced to residents.

Wu cautioned that aftershocks measuring between 5.5 and 6.0 could occur over the next three days to a week.