Yes, but earthquakes have a logarithmic (powers of ten) scale when reporting the magnitude, and a explosive blast (even a nuke) has a powers-of-cube decreasing effect as the weapon yield gets higher.
The earthquake caused by the 2016 nuclear test was 5.1 magnitude,[2][14] similar to the 5.1-magnitude earthquake that accompanied North Korea's previous 2013 nuclear test (which was estimated by South Korea to have a yield of 6–9 kilotons of TNT and Russian estimates of more than 7 kilotons of TNT).[15][16]
https://en.wikipedia.org/wiki/2016_North_Korean_nuclear_test
So if the 5.6 reading the USGS calculated stands, the yield should be well over 10 kilotons?