Hidden jerk in universal creep and aftershocks

Area of Science:

• Rheology
• Materials Science
• Geophysics

Background:

• Materials exhibit creep memory under constant load, described by Andrade's creep law.
• Andrade's law shares connections with the Omori-Utsu law governing earthquake aftershocks.
• Existing empirical laws lack deterministic physical interpretations, hindering parameter confidence.

Purpose of the Study:

• To establish a physical mechanism underlying Andrade's and Omori-Utsu laws.
• To connect the parameters of these laws with macroscopic material properties.
• To provide a physical basis for anomalous viscoelasticity and acoustic attenuation models.

Main Methods:

• Developed an analogous linear physical mechanism.
• Related the mechanism's parameters to macroscopic material properties.
• Utilized concepts involving jerk (first-order time derivative of stress) instead of viscosity.

Main Results:

• A unified physical mechanism explains both Andrade's creep and Omori-Utsu aftershock laws.
• The mechanism relies on a rheological property involving jerk, not viscosity.
• Justified the constant quality factor model for acoustic attenuation in complex media.

Conclusions:

• The study provides a deterministic physical interpretation for empirical creep and aftershock laws.
• The findings offer confidence in the physical parameters extracted from curve fitting.
• The proposed mechanism has implications for understanding material behavior and seismic phenomena.