SAExploration's is working in the area between Forest Hill and Melder today. Crew with drill buggy and water truck. SAExploration is the one who is permitted to do the 500+ square mile 3D seismic survey for CGG.
Could be. Three different crews, buggies and water trucks working. Does 3D surveys use dynamite or vibration trucks?
Seismic acquisition for either 2D or 3D can use either energy source - depends on surface logistics and energy generation specs they are looking at. Or in wet areas, some sort of "sound source" in the water.
A mix of all energy sources can be used on the same survey.
Shot holes and explosive charges are more expensive but unavoidable if that is the only option that can be utilized.