The feature observed by the scientist in the given case is a normal fault.
A geologic fault in which the hanging wall has moved downward relative to the footwall is considered as a normal fault. Such kind of faults takes place when the two blocks of rock are pulled away from each other, due to tension. A fault in geology refers to a discontinuity or planar fracture in a volume of rock, through which there has been substantial displacement as an outcome of rock-mass movement.