Joint inversion of seismic traveltime and gravity data: A synthetic study using geologically realistic models from the Voisey's Bay deposit
Abstract
Seismic methods provide high resolving potential for use in mineral exploration. Unfortunately, complicated hard-rock geology can make seismic data processing and interpretation difficult. It may help to overcome these difficulties by jointly inverting seismic tomography data with gravity data. We investigated the viability of deterministic minimum-structure style joint inversion of seismic traveltime and gravity data for the delineation of geological targets from the Voisey's Bay sulfide deposit in Labrador, Canada. These tests also assessed the potential of employing borehole gravity. A number of synthetic Earth models were created based on the geology of the Eastern Deeps zone of the Voisey's Bay deposit. These models were built on triangular (2D) and tetrahedral (3D) unstructured meshes, allowing for efficient generation of complicated, realistic geological structures. 2D models were based on conceptualized models of the Eastern Deeps. A detailed 3D model was built using information from extensive drilling. Single property and joint inversions were performed with seismic traveltimes and both ground-based and borehole gravity. There is a known relationship between seismic velocity and density for both silicate rocks and sulphide minerals for our study area; this lithological relationship was used to design an appropriate coupling strategy in the joint inversions. Joint inversions were able to successfully locate a buried high contrast target with a variety of survey designs. Experimentation with noise levels, mesh design, and various inversion parameters has lead to a better understanding of how to practically apply joint inversion of traveltimes and gravity data to this and similar exploration problems.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFMNS31B1679C
- Keywords:
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- 0545 COMPUTATIONAL GEOPHYSICS / Modeling;
- 0902 EXPLORATION GEOPHYSICS / Computational methods: seismic;
- 0903 EXPLORATION GEOPHYSICS / Computational methods: potential fields;
- 0915 EXPLORATION GEOPHYSICS / Downhole methods