ERSC 3V93 Lecture Notes - Lecture 9: Bulk Density, Shuttle Radar Topography Mission, Gravimeter
27 Apr 2016
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Document Summary
The bulk density of rock or sediment is controlled by mineral content, porosityand pore fluids. Dry bulk density d = m (1- pt: where pm = density of minerals, pt = total porosity. Wet bulk density w = m + ( f pe: psat = saturated porosity, f = fluid density. Apply range of trial densities to bouguer and terrain corrections. Best density estimate curve with least correlation with topographic surface elevation. Bouguer slab adequately describes the gravitational variations caused by largescale topographic variations (those that can be approximated by a slab) Does not address variations associated with extremes in topography near an observation point. However under estimates the correction on mountains, and over estimates on mountains near measurement point. Local gravity effects also from buildings or other structures. 0. 5 m thick brick wall can induce anomaly of about . 03 gu (0. 003 mgal) at 5 metre distance. Terrain corrections can be estimated using a.
