28 earthquakes felt in central Taiwan sign of big one? Hard to say: experts

Experts say 28 tremors felt in Nantou's Zhushan Township are not necessarily a sign of an impending massive quake

CWB map of Monday's quake in central Taiwan.

TAIPEI (Taiwan News) -- At 8:38 a.m. a magnitude 3.8 earthquake struck near Nantou County's Zhushan Township, the 28th temblor to strike the same spot since late Saturday (Nov. 11) evening, but experts cannot say for certain that this is a precursor to a much larger seismic event. 

On Saturday evening a series of 27 quakes began to hit the area around Zhushan Township last lasted well until Sunday morning, with the largest being a magnitude 5.1 striking at 8:22 p.m. Zhushan actually saw its first quake earlier on Saturday morning, followed by two others, but seismic activity did not pick up again until after 7 p.m.

Though scholars said that it is extremely rare for so many earthquakes to hit the same spot in such a short period of time, the Central Weather Bureau (CWB) said that they are still within the range of a normal energy release, but it advises citizens to beware of quakes in the range of 4 to 5 on the Richter scale for the next couple weeks. 

Before the magnitude 7.3 Kumamoto earthquake struck Japan in 2016, there was first a magnitude 6.5 earthquake, followed by 50 temblors over 4.5 on the Richter scale. Is the situation in Nantou County the same?

The CWB said that the continuous quakes in Zhushan Township are a normal release of energy, the geology is different from the Kumamoto earthquake, and the probability of these triggering a major quake is low. 

At a press conference, Hsiao Wen-chi (蕭文啟) at the Seismological Information Center told reporters that the 5.1 quake that struck on Saturday was the main shock and the subsequent quakes were aftershocks. As for the possibility that this would be a precursor to a much larger quake, he said based on experience in previous years in Taiwan, this is unlikely. 

Furthermore, a National Taiwan University professor of geology told TVBS that although it is extremely rare to have over 20 earthquakes in western Taiwan over the course of one or two days, as for whether this is a sign of a major seismic event, "In fact, we cannot say for certain."

The CWB reiterated that though the weekend's quakes were normal releases of energy, it cannot rule out more earthquakes ranging from a magnitude 4 to 5 in the area over the next couple of weeks, and as for much larger quakes, it remains to be seen. 

While most earthquakes in Taiwan occur off or near the east coast, in the counties of Yilan, Hualien and Taitung, Central Taiwan also registers quakes occasionally.

One of the most serious quakes in modern Taiwan history, the September 21, 1999 “921” quake, was centered on the town of Jiji in Nantou County. More than 2,400 people died across the island, often in collapsed apartment buildings.