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Was deadly Hualien quake linked to Milun Fault? Here's expert views

2018/02/08 16:28:58

Taipei, Feb. 8 (CNA) There have been mixed opinions put forward as to whether a fault line in downtown Hualien is to blame for Tuesday's magnitude 6.0 earthquake that had taken at least nine lives and left several buildings severely damaged as of Thursday.

According to the Central Geological Survey (CGS) under the Ministry of Economic Affairs, it is likely that the temblor was connected to the Milun Fault, which runs southwest from the Qixingtan shoreline to the west side of Meilun Mountain and turns south-southeast under downtown Hualien.

The 7.2-kilometer fault line finishes south of Hualien City at sea.

CGS Deputy Director Tsao Shuh-jong (曹恕中) pointed out that most of the buildings damaged in the quake, including the Marshal Hotel and the Yun Men Tsui Ti commercial and residential building, sit on the fault line.

A CGS team has been dispatched to the site to find out if there is a continuous bulge in the ground above the fault, which Tsao said could determine the cause of the earthquake, with the result expected to be released in two days.

In 2016, the CGS designated the region around the Milun Fault a geologically sensitive area.

Several earthquakes off the coast of Hualien in 1951 with a magnitude of higher than 7.0 were likely connected to the fault, CGS data shows.

At that time, the ground near the Qixingtan area rose by 40 centimeters, according to the data.

However, the Central Weather Bureau (CWB) said more evidence is needed before jumping to that conclusion.

Lu Pei-ling (呂佩玲), deputy director of the CWB's Seismological Center, said the mechanism of Tuesday's earthquake remains unclear.

The bureau's former director-general, Shin Tzay-chyn (辛在勤), pointed out that the last time activity was recorded for the Milun Fault was in 1986, and resulted in a magnitude 6.2 earthquake.

It is unlikely that a fault would become active after only around 30 years, according to Shin.

Still other scholars have expressed different views.

Yen Horng-yuan (顏宏元), director of National Central University's Department of Earth Science, told CNA that the Milun Fault could be the cause of the earthquake.

However, he noted that it is an independent fault line, which means its activity is not likely to trigger nearby fault lines, including the Lingding Fault and the Rueyshui Fault in the south.

Meanwhile, Chen Kuo-chang (陳國昌), acting director of the CWB's Seismology Center, said there are signs that the aftershocks from Tuesday's earthquake are moving southward.

"We need to look closely into the aftershocks because if they continue and intensify, they could trigger another major earthquake," he said.

(By Lee Hsin-Yin, Liao Yu-yang and Chen Wei-ting)