Counterpoint: wikipedia shows a formula that puts it at 44kT[1]. However there is a note that it can vary greatly depending on the fraction of energy that is converted to seismic waves (this formula assumes 0.5%);

That being said, 44kT is still way below what one would expect for a fusion bomb, and low even for a boosted fission bomb.

1: https://en.wikipedia.org/wiki/Moment_magnitude_scale#Nuclear...