SEOUL (Yonhap) -- An international agency on banning nuclear tests announced on Saturday it has adjusted the magnitude of the artificial quake following North Korea's recent nuclear test.

The U.N.'s Preparatory Commission for the Comprehensive Nuclear-Test-Ban-Treaty Organization (CTBTO) said on its Web site that the magnitude of the Feb. 12 quake was confirmed as 4.9, lower than its initial announcement of 5.0.

The CTBTO said 96 international monitoring stations had sent data related to the seismic activity for analysis.

The Korea Meteorological Administration (KMA) and Korea Institute of Geoscience & Mineral Resources (KIGAM) had both said on the day of the nuclear test that the quake had a magnitude of 4.9.

The CTBTO said 22 monitoring stations detected the first North Korean nuclear test in 2006, and 61 stations detected the second such test in 2009.

The increase this year was "due to the rise in the number of stations in operation as well as the larger magnitude of the 2013 test," the CTBTO said.

The U.N. agency said the artificial quake from the first test rated at 4.1 and the one from the following test had a magnitude of 4.5.