Amplitude effects on seismic velocities: How low can we go?

Area of Science:

• Geophysics and Materials Science: Focus on elastic characterization of SiO2 polymorphs, particularly alpha-quartz, relevant to seabed materials and geoscientific exploration.

Background:

• Seismic wave propagation in minerals is crucial for geophysics, especially in oil exploration.
• Accurate elastic characterization of materials like alpha-quartz is essential for understanding seismic properties.
• Previous work established a novel simulation method to observe wave propagation in crystals.

Purpose of the Study:

• To systematically investigate and refine a new simulation methodology for calculating seismic velocities.
• To explore different implementations of perturbation sources and their impact on wave propagation.
• To assess the influence of perturbation amplitude and force fields on calculated seismic velocities.

Main Methods:

• Developed and tested new techniques for creating longitudinal and transversal perturbations in simulation boxes.
• Analyzed the effect of perturbation amplitude on simulated S- and P-wave velocities.
• Evaluated various force fields for describing interatomic interactions in alpha-quartz.

Main Results:

• Seismic velocities showed no dependence on the method of perturbation creation or its amplitude.
• Calculated velocities demonstrated excellent agreement with experimental S- and P-wave data.
• The methodology proved robust and reliable, validated by behavior under stress and in the presence of vacancies.

Conclusions:

• The refined simulation method is robust and reliable for calculating seismic velocities in geophysically relevant materials.
• This approach offers precise control over sample features and perturbation parameters.
• Opens new avenues for systematic seismic velocity calculations in materials science and geophysics.