Uncertainty loops in travel-time tomography from nonlinear wave physics

Area of Science:

• Geophysics
• Seismology
• Geodynamics

Background:

• Image uncertainty estimation is crucial for interpreting geoscientific tomographic maps.
• Current methods often rely on linearized approaches, potentially missing complex uncertainty structures.

Purpose of the Study:

• To identify and characterize novel uncertainty topologies in geoscientific tomographic maps.
• To investigate the implications of these topologies for interpreting seismic velocity anomalies.

Main Methods:

• Analysis of Love wave tomographic uncertainties.
• Identification of 'loop' structures in uncertainty estimations.
• Exploration of 2nd and higher-order wave physics aspects.

Main Results:

• Discovery of widespread 'loop' uncertainty topologies, dominating approximately one-third of UK Love wave tomographic uncertainties.
• Demonstration that while seismic speeds are well-constrained, anomaly locations exhibit significant uncertainty.
• Observation that these loops arise from non-linear wave physics.

Conclusions:

• Standard linearized methods may be insufficient for capturing complex tomographic uncertainties.
• Higher-order methods are recommended for more accurate and comprehensive uncertainty analysis in geophysics, physical sciences, and medicine.
• The identified loops fundamentally alter the interpretation of seismic anomalies.