A team of U.S. geologists says it has located the site of North Korea's second nuclear test in May last year.

The team is led by Lianxing Wen and Hui Long of State University of New York at Stonybrook, and made the announcement in the January-February edition of the academic journal Seismological Research Letters.

The team say the nuclear test was conducted in a region with a latitude of some 41 degrees and 17 minutes and a longitude of 129 degrees and four minutes. The horizontal uncertainty of the location they found is plus or minus 140 meters.

The calculation points to a region south of a mountain in Kilju, North Hamkyong Province.

The team determined the site based on calculations of seismographic data measured in South Korea, Japan and China when the North conducted its first and second nuclear tests.

The survey's assessment of the nuclear test site location in the North is considered to be the most precise with a margin of error of 7.6 kilometers.