Geophysical Inverse Theory

1 What Is Inverse Theory 1
1.1 Too many models..............................4
1.2 No unique answer..............................4
1.3 Implausible models.............................5
1.4 Observations are noisy...........................6
1.5 The beach is not a model..........................7
1.6 Summary..................................8
1.7 Beach Example...............................8
2 A Simple Inverse Problem that Isn’t 11
2.1 A First Stab atρ..............................12
2.1.1 Measuring Volume.........................12
2.1.2 Measuring Mass...........................12
2.1.3 Computingρ............................13
2.2 The Pernicious E?ects of Errors......................13
2.2.1 Errors in Mass Measurement....................13
2.3 What is an Answer?............................15
2.3.1 Conditional Probabilities......................15
2.3.2 What We’re Really(Really)After.................16
2.3.3 A(Short)Tale of Two Experiments................16