For the following scenarios tell whether you think a refraction survey or a reflection survey would give better results and explain why. Also state how you think the geophone strands and seismic source should be set up (examples: refraction survey with shots at either end or both ends, or a reflection survey with a shot in the center)
1) You have been hired to do a survey to search for old tunnels that are rumored to be in the area, previously used to smuggle people across the US-Mexico border. The tunnels are not expected to be exceptionally deep underground.
2) You are doing a survey to contour the water table across a 2 mile stretch of land between a river and a farmer's field. He wont let observation wells be drilled in his field, but the water table data needs to be gathered.
3) A basalt flood plain covers what archaeologists believe to be the ruins of a stone castle and its surrounding farmland. When a rift erupted approximately 500 years ago the basalt flows covered the already demolished castle. The basalt layer is thick enough that it could conceal rubble from stone walls and foundations and would not be easy to dig through or see through with ground penetrating radar. Also, Do you think a seismic survey could locate the buried castle ruins in the middle of the buried farmland?