The conventional magnitude scale $M$ becomes inaccurate for great earthquakes due to the saturation of seismic wave wavelengths. To address this, the strain energy drop $\Delta E$ is estimated using the relation $M_{w} \sim \Delta E / \Delta \sigma$, where $\Delta \sigma = \Delta \sigma / 2a$ and $M_{w} = (\Delta \sigma / 2a) M_{s} \sim M_{s} / (2 \times 10^{6})$. A new magnitude scale $M_{w}$ is defined through the standard energy-magnitude relation $\log W_{s} = 1.5 M_{w} + 11.8$, where $W_{s}$ is the seismic wave energy. This scale is more suitable for great earthquakes, with a maximum value of 9.5 for the 1960 Chilean earthquake. The temporal variation of $W_{s}$ shows a significant increase from 1950 to 1965, correlating with the Chandler wobble amplitude. The number of moderate to large earthquakes increased sharply during the period when $W_{s}$ was largest, suggesting a causal relationship between wobble amplitude and seismic activity. The study suggests that an increase in wobble amplitude triggers worldwide seismic activity, accelerates plate motion, and leads to great decoupling earthquakes, which in turn reduces moderate to large earthquake activity.The conventional magnitude scale $M$ becomes inaccurate for great earthquakes due to the saturation of seismic wave wavelengths. To address this, the strain energy drop $\Delta E$ is estimated using the relation $M_{w} \sim \Delta E / \Delta \sigma$, where $\Delta \sigma = \Delta \sigma / 2a$ and $M_{w} = (\Delta \sigma / 2a) M_{s} \sim M_{s} / (2 \times 10^{6})$. A new magnitude scale $M_{w}$ is defined through the standard energy-magnitude relation $\log W_{s} = 1.5 M_{w} + 11.8$, where $W_{s}$ is the seismic wave energy. This scale is more suitable for great earthquakes, with a maximum value of 9.5 for the 1960 Chilean earthquake. The temporal variation of $W_{s}$ shows a significant increase from 1950 to 1965, correlating with the Chandler wobble amplitude. The number of moderate to large earthquakes increased sharply during the period when $W_{s}$ was largest, suggesting a causal relationship between wobble amplitude and seismic activity. The study suggests that an increase in wobble amplitude triggers worldwide seismic activity, accelerates plate motion, and leads to great decoupling earthquakes, which in turn reduces moderate to large earthquake activity.