title: Uncertainty loops in travel-time tomography from nonlinear wave physics.
abstract: Estimating image uncertainty is fundamental to guiding the interpretation of geoscientific tomographic maps. We reveal novel uncertainty topologies (loops) which indicate that while the speeds of both low- and high-velocity anomalies may be well constrained, their locations tend to remain uncertain. The effect is widespread: loops dominate around a third of United Kingdom Love wave tomographic uncertainties, changing the nature of interpretation of the observed anomalies. Loops exist due to 2nd and higher order aspects of wave physics; hence, although such structures must exist in many tomographic studies in the physical sciences and medicine, they are unobservable using standard linearized methods. Higher order methods might fruitfully be adopted.
authors.affiliation: School of GeoSciences, The University of Edinburgh, Grant Institute, The King's Buildings, James Hutton Road, Edinburgh EH9 3FE, United Kingdom.
authors.forename: Erica
authors.initials: E
authors.lastname: Galetti
authors.affiliation: School of GeoSciences, The University of Edinburgh, Grant Institute, The King's Buildings, James Hutton Road, Edinburgh EH9 3FE, United Kingdom.
authors.forename: Andrew
authors.initials: A
authors.lastname: Curtis
authors.affiliation: School of GeoSciences, The University of Edinburgh, Grant Institute, The King's Buildings, James Hutton Road, Edinburgh EH9 3FE, United Kingdom.
authors.forename: Giovanni Angelo
authors.initials: GA
authors.lastname: Meles
authors.affiliation: British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, United Kingdom.
authors.forename: Brian
authors.initials: B
authors.lastname: Baptie
mesh_terms: D055593:Geological Phenomena; D008377:Maps as Topic; D008962:Models, Theoretical; D017711:Nonlinear Dynamics; D010825:Physics / Q000379:methods; D014054:Tomography / Q000379:methods*; D035501:Uncertainty