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Gravity/topography admittance inversion on Venus using niching genetic algorithms
Author(s) -
Lawrence Kristin P.,
Phillips Roger J.
Publication year - 2003
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2003gl017515
Subject(s) - lithosphere , geology , mantle (geology) , venus , gravity anomaly , volcano , geophysics , inversion (geology) , crust , free air gravity anomaly , geodesy , seismology , bouguer anomaly , tectonics , physics , paleontology , astrobiology , oil field
We used niching genetic algorithms (NGAs) to invert localized Venus gravity/topography admittance over lowland regions Atalanta and Lavinia Planitiae, as well as volcanic rise Atla Regio for comparison. Assuming both top (topography) and bottom (mantle density anomalies) loads, we calculated theoretical admittance using thin elastic shell models. We inverted admittance for crustal thickness, elastic lithosphere thickness, mantle density anomaly thickness, and ratio ( p z ) of mantle density anomaly to topographic load. NGA inversion provides an efficient means of finding globally optimal and sub‐optimal solutions. Error analyses of all three regions show that p z is a robust estimate; there is significant trade‐off between elastic lithosphere and mantle anomaly thicknesses, while crustal thickness is ill‐constrained. Optimal models suggest that mantle density anomalies are ∼+1 to 2% underlying lowland regions and ∼−3 to −4% underlying Atla Regio.