GPS and Gravity Field Assignment - an evolving assignment with your presentations due in class the week before finals

The objective here is to initiate and complete a gravity survey using the CG3 gravity meter and our Trimble GPS equipment which will yield the submeter elevation control we require for the gravity survey.  On March 12th, Tony Berthelote introduced the general problem we will work on which is coordinated with his Ph.D. research. Tony needs a good estimate of depth to bedrock across the valley, which will make a great small-scale gravity study. There are existing data and interpretations that have left some blanks in the map - we'll fill those blanks in with gravity observations and a final interpretation.

There are four general areas where we need additional gravity observations:

1. Hellgate Canyon (figure 1)
2. Bandmann Flats (figure 2)
3. Milltown Dam (figure 3)
4. Stimpson site (figure 4)
5. Clark Fork River above the dam (figure 5)

Teams of two to three can work together to collect the data. However, each individual is responsible for their own data and the processing and interpretation of those data. I want a well-written report on your experiment from each participant.

The complete Gravity Flow Chart has all the details of completing a gravity survey, we've gone over most of the steps in class, will go over some more on a rainy day, and I am available for clarification. A short list of tasks goes like this:

• collect a sufficient number of GPS and gravity observations that are correctly spaced for our experiment
• drift correct those points
• calculate the free air anomaly, simple, and complete Bouguer anomalies
• compare your results with others in your group
• you'll probably find Surfer and GravCadW handy for presentation and interpretation of your data.
• Turn in a well-presented, nicely written and illustrated report detailing your experimental method and interpretation with no more than three pages of precise text.