Whenradiologically feasible, the complete crater surveys are to be done as stated above. These will require a four-man survey crew to work approximately 5 days per shot. A monitor will be required at these times, which may be 1 to 4 months after the shots. Two laborers are to accompanythe crews after the surveys, The damaged stakes, together with their locations, are to be part of the data. It should be-realized tfat time estimates given above are highly dependent upon severity of radiological contamination in the tower area and hence highly optimistic. Logistic support and monitors must be furnished to the working crews. Memorandum for: CTU 3.1.7 From: CTU 3.1.1 Subject: CRATER SURVEYS, ALL SITES LESS E+ Reference: SDF -2181 The following procedure is to be considered an elaboration of SDF-649, dated 20 March 1951: 1, Determine elevation of undisturbed ground in immediate vicinity of each stake. 2. Determine, with maximum feasible field accuracy, direction with respect to Ground Zero of bent portion of all stakes. 3. File reference mark on all stakes at bend. 4. Determine elevation of above reference mark for all stakes. 5. Establish by survey, postshot position of all stakes to accuracy consistent with accuracy of preshot stake survey. , 6. Completely excavate nearest-in stake and one medium-distance stake on eachline. 7. If the two stakes specified in Step 6 are straight below the top bend, pull carefully the remaining stakes in the line. 8. If the two stakes specified in Step 6 are not straight below the top bend, excavate carefully all stakes up to radial distances where the stakes become straight below the top bend. 9. Attach to all stakes tags indicating preshot location (distance and azimuth to Ground Zero) and ship stakes, together with all above data, to: Edward J. Zadina, Los Alamos Scientific Laboratory, P.O. Box 1663, Los Alamos, N. Mex. 25