Positive Answer on the Existence of Correlations between Positive Earthquake Magnitude Differences

The identification of patterns in space, time, and magnitude, which could potentially encode the subsequent earthquake magnitude, represents a significant challenge in earthquake forecasting. A pivotal aspect of this endeavor involves the search for correlations between earthquake magnitudes, a task greatly hindered by the incompleteness of instrumental catalogs. A novel strategy to address this challenge is provided by the groundbreaking observation by Van der Elst (Journal of Geophysical Research: Solid Earth, 2021) that positive magnitude differences, under specific conditions, remain unaffected by catalog incompleteness. In this Letter, we apply these conditions and provide clear and compelling evidence for the existence of correlations between consecutive positive magnitude differences. Our findings strongly support the scenario where the distribution of subsequent earthquake magnitudes depends on the magnitude of the triggering earthquake.