Gravity and Electromagnetics - 2005- Take home final!

Rule: You can talk over how to do surveys, etc. but I want everybody to write up their own bids - my autocratic rules preclude collusion and price fixing. Due on or before Thursday, May, 12th, 3:21 pm.

Do one of these two bids:

Request For Bid: Gravity Survey

A client is concerned about groundwater volumes and flow in the middle Rattlesnake Valley in the area between the north and south borders of Figure 1. As an initial step, the client wants you to design a gravity survey to determine the shape of the contact between the valley fill and the bedrock. After the completion of the gravity survey, the client wants a recommendation on where to do ground penetrating radar (GPR) profiles to test the gravity modeling. Rocks of the Precambrian Belt Supergroup are exposed at the sides of the valley; the fill of the Rattlesnake Valley is probably Quaternary alluvium. Rocks of the Precambrian Belt Supergroup (~2900 kg/m3) are exposed at the sides of the valley; the fill of the Rattlesnake Valley is probably Quaternary alluvium (~2200 kg/m3).

• A brief introduction with a concise description of the problem including your initial estimate of the bedrock surface and how you made that estimation
• Whether (and why) your survey will be based on profiles or a grid of observations, and your proposed distribution of observations
• Equipment to be used including its inherent uncertainty
• A description/explanation of your proposed procedures (so they can be compared to other bids)
• A description of the project report you intend to submit on completion (nature of data, figures and graphs)
• A summary of possible problems/limitations of the gravity survey
• A short description of how you will decide where to specify four follow-up GPR lines and what they might show
• A detailed breakdown of your survey costs and your total bid for the gravity component of the project. You should consider travel time, time in the field, time in the lab, and time to write the report; base it on $40/hour.

Your bid should be submitted as a memo and should be no longer than three printed pages not including figures, maps, and budget page. If you need to you may include additional items in an appendix.

Request for Bid: Ground Penetrating Radar Survey along with ???

A local historical society has developed some literature-based leads about grave sites asociated with early settlers in the Bitterroot Valley and surrounding areas. Montana's laws are restrictive concerning grave digging (at least for occupied graves). Thus, the historical society is looking for some assistance in developing a non-invasive survey to confirm their suspicions about the locations of historical graves. They think there are three aligned graves in an area about the size of a soccer field. The field is mostly open, with a few large ponderosa pines scatterred around.

As bidding contractor, you are responsible for experimental design, fieldwork, data acquisition, data processing, and interpretation. You should specify the equipment from my lab that you will use but need not include rental expense in your bid.

Your submitted bid should include:

• A brief introduction with a concise description of the problem
• The equipment you propose to use, the values you propose to measure, and why
• Line spacing and geometry for the survey
• A description/explanation of your proposed procedures (so they can be compared to other bids)
• A description of the project report you intend to submit on completion (nature of data, figures and graphs)
• An summary of possible problems/limitations of the survey
• A detailed breakdown of your survey costs and your total bid for the project. You should consider travel time, time in the field, time in the lab, and time to write the report; base it on $40/hour.

Your bid should be submitted as a memo and should be no longer than two printed pages not including figures, maps, and budget page. If you need to you may include additional items in an appendix.

Part Two- Follow up on your gravity or GPR project with electrical resistivity

Do a field and report project to follow up on the gravity or GPR survey assignments you have already completed. In either case, the proposed project should test or extend previous results, whether those results are from your particular survey or class results. For example, if you want to follow up on the gravity project, you could collect resistivity data to fill in and confirm initial suspicions from the combined group data. Alternatively, you could do an independent resistivity or EM31 project. I want you to talk over the proposed with me first to make sure it is of about the right depth, and I want a final, written report of about 3-4 pages following the report outline you are familiar with.

Part Three: A flexural problem.

Suppose a first, and much later a second, thrust sheet impinges on some continental crust. Assume both are the same mass. Using the equation for flexure of a broken plate from class, graph the flexural profile following the first sheet and then the second sheet. From this, calculate the change in angle of the angular unconformity caused by the second thrusting event. For the parameters you need, use those I suggested in class for the Purcell Anticlinorium problem. Turn in calculations and graphs - neatly and precisely explained.