Episode 52 - "You pay for significant digits"

Last week we talked about glaciers, a basic staple of any geology education. That means it’s only fair to talk about a geophysics staple this week. We can measure gravity at different locations and use it to help figure out what’s under our feet. That and another great Fun Paper this week!

• It’s All About Pentiums (Weird Al)

Gravity Basics

• All geophysical methods are based on measuring some kind of physical property difference.
• Gravity is sensitive to the density of the material below the measurement.
• “Big G"
• gal (unit)
• Density for any rock varies widely.
• Gravity from impact structures

Measuring gravity

• Absolute gravimeter
• Relative gravimeter
• Zero-Length Springs
• Differential GPS

Corrections

• Examples of the more common corrections
• Eötvös effect
• John’s explanation of Coriolis Force and Toilets
• Isostasy
• Bouguer Anomaly
• FORTRAN Talwani Example
• Original Talwani Paper

Fun Paper Friday

• Alarcón, Héctor, et al. “Self-Amplification of Solid Friction in Interleaved Assemblies.” Physical Review Letters 116.1 (2016): 015502.
• Semis pulling on phone books
• Mythbusters

Contact us:

Show - www.dontpanicgeocast.com - @dontpanicgeo - show@dontpanicgeocast.com

John Leeman - www.johnrleeman.com - @geo_leeman

Shannon Dulin - @ShannonDulin