BBC R4 'Inside Science' reports on a study from the University of Colorado which claims that the frequencies of magnitude >7M earthquakes goes up with reduction of equatorial dimension correlating with millisecond differences in LOD.
"What might the length of the day have to do with the likelihood of destructive earthquakes around the world? According to Professors Rebecca Bendick and Roger Bilham, there's a correlation between changes in the rate at which the Earth rotates and the incidence of earthquakes of Magnitude 7 and above. The rotation speed of the planet increases and decreases over periods of years and decades. From their research, the earth scientists say that there's an substantial increase in the number of powerful earthquakes around the world five years after the Earth attains a peak in its spin speed and enters a period of slow down. The difference in day length is tiny but it is enough, say the researchers, to trigger already stressed faults in the crust to move sooner than later."