(ATTN: UPDATES throughout with more info)
SEOUL, May 15 (Yonhap) -- A 4.5 magnitude earthquake struck off the east coast city of Donghae on Monday, the weather agency said, but no damage has been reported.
The quake occurred in waters about 59 kilometers northeast of Donghae, located 182 km east of Seoul, at 6:27 a.m., according to the Korea Meteorological Administration (KMA).
The epicenter was at 37.99 degrees north latitude and 129.72 degrees east longitude, with the depth estimated at 32 km, the agency said.
It was the strongest quake to occur on the Korean Peninsula or waters around it so far this year.
Similar quakes have been reported off the east coast in recent weeks, though they caused no damage.
A total of 18 reports of tremors being felt have been filed from Donghae and two nearby cities, but no reports of damage have been received, according to fire authorities.
The weather agency had initially put the scale of the Monday earthquake at 4 magnitude, based on the analysis of P waves that travel faster than other seismic waves, but shortly revised up the figure after further analysis.
The seismic intensity scale measuring the severity of ground shaking was 3 in Gangwon Province that houses Donghae and the nearby North Gyeongsang Province, meaning the quake could be felt "significantly" by those staying indoors, especially on upper floors.
So far this year, 44 earthquakes of 2 magnitude or stronger have hit the peninsula or its surrounding waters, but all but the Monday quake were under magnitude 4.
The previous earthquake of a similar size was the 4.9 magnitude quake that shook waters off Jeju Island on Dec. 14, 2021.
Since 1978, 28 earthquakes of 4.5 magnitude or stronger have occurred on the peninsula or its nearby waters, according to the agency's data.
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