The relationship between the global seismicity and the rotation of the Earth

Possible relationship between seismicity and the length of day (LOD) variation was investigated for a single seismic event and in global case. 1. On the basis of a theoretical model investigation it was found, that even in case of the largest instrumentally recorded earthquakes, the amplitude of the generated LOD variation is below the associated accuracy of the observations. 2. The latitude distribution of the seismic energy and the number of the earthquakes of magnitude (M) equal or greater than seven are maximal for latitudes around 48.2◦. It was shown by model calculations that this phenomenon takes place when the variation of geometric flattening of the Earth, due to the changes in rotation speed, occurs. Significant correlation was found in the course of the XXth century between the changes in LOD and the annual number of Mgeqslant7 seismic events. It is therefore likely, that the variations of LOD have some significant influence on seismic activity.