Aftershocks in a frictional earthquake model.

Area of Science:

• Geophysics
• Computational Seismology
• Physics of Earthquakes

Background:

• Empirical seismological laws, like the Gutenberg-Richter and Omori laws, describe earthquake frequency-magnitude distributions and aftershock decay.
• Existing physical models often struggle to simultaneously explain both major empirical laws governing earthquake behavior.

Purpose of the Study:

• To develop a minimal physical model that can reproduce both the Gutenberg-Richter and Omori laws.
• To identify the essential physical ingredients required for a unified frictional model of earthquakes.

Main Methods:

• Elaboration of a spring-block model inspired by existing frameworks.
• Incorporation of two key physical elements: aging of contacts within the sliding interface and elasticity of the sliding plates.

Main Results:

• The developed minimal physical model successfully reproduces the Gutenberg-Richter law, characterizing earthquake magnitude distributions.
• The model also accurately replicates the Omori aftershock law, describing the decay rate of aftershocks over time.
• Demonstration that aging contacts and elastic plates are sufficient to capture both seismic laws.

Conclusions:

• Simultaneous aging of contacts and elasticity of plates are minimal, yet sufficient, ingredients for a physical model explaining key earthquake laws.
• This unified frictional model offers a more comprehensive understanding of earthquake physics and scaling laws.