Airy and Pratt isostasy models
Modelos de isostasia de Airy y Pratt
- Date
- 1855 · confidence high
- Place
- Dehradun, Uttarakhand, India
- Credited to
- George Biddell Airy and John Henry Pratt
- Field
- Cosmos & Earth
What was discovered
Pratt calculated that the Himalayan mass should deflect the plumb line far more than measured in the survey of India; Airy explained it with roots of light crust floating in denser mantle, while Pratt assumed lower densities beneath mountains. The term 'isostasy' was coined by Dutton in 1889.
Both models were published in 1855; Airy proposed his hypothesis after Pratt's measurement. Later measurements (Vening Meinesz, Heiskanen) showed that each applies depending on the region. The place is the seat of the Great Trigonometrical Survey.
What it led to
- crustal equilibrium and post-glacial rebound
- Bouguer gravity anomalies and gravity maps
- crustal thickness models