Cross hole seismic surveys involve measurement of the travel time of seismic energy transmitted between two or more boreholes in order to derive information on the elastic properties of the intervening materials.
Crosshole method is performed for the detection of low velocity zone which is undetectable with conventional surface seismic. A method for determining soil dynamic modules by using P wave velocity and S wave velocity. Implementation is carried out within the borehole. This method is required two or more boreholes for implementation forwhy wave source and receivers shall be in separate boreholes. Seismic waves are detected with multi-axis geophones. Data from geophones are collected by moving source and receiver with fixed (normally 1 m-2 m) increments.