CWA warns of aftershocks of over magnitude 5 in coming days

Taipei, Jan. 21 (CNA) The Central Weather Administration (CWA) on Tuesday warned of aftershocks measuring magnitude 5 or higher in southern Taiwan over the next three days, after a magnitude 6.4 earthquake jolted Chiayi County earlier in the day.

The magnitude 6.4 earthquake, the epicenter of which was 37.9 kilometers southeast of Chiayi County Hall at a depth of 9.7 kilometers, rocked Chiayi County at 12:17 a.m., CWA data showed.

The quake's seismic intensity was highest in the southern county's Dapu Township, measuring 6- on Taiwan's 7-tier scale.

The earthquake also registered a seismic intensity level of 5- in Tainan and Kaohsiung, according to the CWA.

The magnitude 6.4 earthquake -- the strongest Dapu Township had experienced in 61 years -- shook the ground for about 43 seconds, causing vibrations of level 2 or higher, according to Wu Chien-fu (吳健富), director of the CWA's Seismological Center.

As of 11 a.m. on Tuesday, 55 aftershocks had already been felt in southern Taiwan, mostly in Tainan City's Nansi and Nanhua districts, following the 12:17 a.m. quake, center data showed. There were 14 measuring magnitude 4 or higher, with two aftershocks measuring 5 and 5.2.

According to former CWA Seismological Center Director Kuo Kai-wen (郭鎧紋), Tuesday's magnitude 6.4 earthquake originated in a location near where the Baihe earthquake struck Tainan in 1964. The two seisms had similar geological structures, he noted.

Kuo cautioned the public in Chiayi and Tainan to be careful of moderate-major earthquakes in the month ahead as Taiwan had not experienced temblors of over magnitude 6 for more than 150 days.

On average, Taiwan has a 1 percent chance of being hit by an earthquake of more than magnitude 6 on a daily basis, he explained.

According to the Seismological Center's records, various earthquakes with magnitudes measuring between 5 and 6 have shaken areas within a 30-kilometer radius around Dapu Township, including a magnitude 6.3 Baihe earthquake in 1964 and a magnitude 7.1 earthquake in Chungpu in 1941.