Full Spectrum Tomography
The physical properties of the Earth are unique and exact, even if various geophysical datasets can only ‘see’ a subset (i.e. spatial scale, property type) of its features. Our methodology has unified all major types of data constraints on physical properties of rocky planets in a single all encompassing inversion scheme.
Progress in tomographic modeling is driven by diverse data, ranging from astronomic-geodetic constraints to full seismic waveforms and derivative measurements of body waves (~1 – 20s), surface waves (~20 – 300s) and normal modes (~250 – 3200s).
Full-spectrum tomography (FST) employs diverse observations spanning a broad period band (~1 - 3200s) to constrain physical properties – seismic velocity, anisotropy, density, attenuation and topography of discontinuities - in variable spatial resolution. Joint inversions account for different depth sensitivities to physical parameters and also reduce inter-parameter tradeoffs.
Physical models describing the bulk Earth properties (1D) and lateral heterogeneity (3D) have been constructed using the FST technique. These results shed new light on the current state of the Earth and its dynamic evolution.
-
Processed waveform (Left) & spectrum (Right) at Charters Towers, Australia from MW 9.1 2004 Sumatra Earthquake. Derived data types are listed; those in yellow are array-based techniques. Do tomographic techniques that use processed versus derived measurements “see” the same heterogeneity?
-
Full Spectrum Tomography (FST) models the full spectrum of seismic data spanning 1-3000 s to constrain different types of heterogeneity in variable spatial resolution. Average Earth data, marked by *, ensure that bulk properties of 3D models are optimized simultaneously.
-
Sensitivity of different data sets represented by global average of diagonal elements of the inner-product matrix [GTG from Gm=dobs]. Zoomed panels for VS on the right show cumulative sensitivities for sub-types of data, & for all data combined.