Nine earthquakes with magnitudes ranging between 3.6 and 5.1 rattled eastern Taiwan between late Tuesday and early Wednesday, according to the Central Weather Bureau's Seismology Center.

Although the quakes were felt by residents in the eastern counties of Taitung and Hualien, no damage or casualties have been reported, authorities said.

The first of the nine quakes, a magnitude 4.7 temblor that occurred at 10:29 pm Tuesday, was centered 9.8 kilometers northwest of the Chenggong seismological monitoring station in Taitung County and struck at a depth of 5 km, said Seismology Center Director Kuo Kai-wen.

The biggest quake of the series, a magnitude 5.1 quake, struck at 4:49 am Wednesday at a depth of 10 km. Its epicenter was around 5.4 km northwest of the Chenggong seismological monitoring station.

A magnitude 4.1 aftershock occurred six minutes later at a nearly identical depth and location. Its epicenter was located 5.5 km northwest of the Chenggong station, and its focus was at a depth of 9.8 km.

Kuo said that although the frequency of preshocks and aftershocks was relatively high, their magnitudes were not strong and the areas affected were limited.

Even though the main shock reached a magnitude of 5, it lasted for only 1.18 seconds and had little impact on the safety of buildings in the area, Kuo said.

Noting that the Chenggong area lies where the Eurasian and Philippine Sea tectonic plates converge, Kuo said the area is earthquake-prone, with the plates being pushed down an average of 8 centimeters annually.

By helping release energy that has been building up between the tectonic plates, the latest series of earthquakes may have helped prevent a potentially larger earthquake capable of inflicting more serious damage, he added.

China Daily/CNA

(HK Edition 04/15/2010 page3)