Verifying the Magnitude Dependence in Earthquake Occurrence

Area of Science:

• Seismology
• Earthquake Science
• Geophysics

Background:

• Magnitude dependence in earthquake triggering has been reported, impacting seismic predictability.
• The cause of this correlation is debated, with possibilities including physical processes or data incompleteness (missing short-term aftershocks).

Purpose of the Study:

• To investigate and resolve the debate surrounding magnitude dependence in earthquake triggering.
• To determine if a correlation between earthquake magnitudes is a physical phenomenon or an artifact of incomplete seismic catalogs.

Main Methods:

• Analysis of a synthetic earthquake catalog generated by a numerical model simulating earthquake statistics.
• Application of the stochastic declustering method to a high-resolution earthquake catalog of the Amatrice-Norcia (2016) sequence.
• Focusing analysis on events above the determined magnitude of completeness to ensure data reliability.

Main Results:

• The study found no statistically significant evidence to support a magnitude correlation in earthquake triggering.
• Analysis of both synthetic and real-world earthquake data led to the rejection of the magnitude correlation hypothesis.

Conclusions:

• The observed magnitude dependence in earthquake triggering is likely not a physical characteristic of seismic processes.
• Data incompleteness, particularly the omission of short-term aftershocks, may explain previous reports of magnitude correlation.
• This finding has implications for understanding earthquake predictability and catalog completeness.