Just thinking aloud!Most deep gully erosion sites in southestern Nigeria seem to be located in a zone that is approximately in a straight line. Similarly, their trends seem to be mostly in the same direction. Is there a possibility that these gullies are following weak zones created by landward/continental extension of the trans-oceanic fractures? Are there possibilities of geological factors?
It is definitively possible. The question is whether the structures are "activelly" controlling the surface (i.e., due to neotectonics) or they are inactive but represent weak zones that are easily eroded.
EXISTING REPORTS SHOW THAT LITHOLOGY, SLOPE, HUMAN ACTIVITIES AND GROUND/SURFACE WATERS ARE KEY FACTORS RESPONSIBLE FOR THE WIDESPREAD OCCURRENCE OF GULLIES IN SOUTHEAST NIGERIA. THE QUESTION IS "WHY THESE GULLIES ARE LESS ABUNDANT IN ADJACENT REGIONS, WITH SIMILAR CHARACTERISTICS" THE ANSWER TO THIS MAY APPEAR IF THE GULLIES ARE STUDIED REGIONALLY WITH MULTIPLE DATASETS INCLUDING TECTONIC DATA
As a counter example, we show that ~800m deep 'gullies' west of Sydney, Australia, are predominantly related to the exhumation by erosion of a pre-existing structural architecture. We found that less than 10% of the range front relief can be related to neotectonic uplift.
MCPHERSON A., CLARK D., MACPHAIL M. & CUPPER M. 2014. Episodic post-rift deformation in the south-eastern Australian passive margin: evidence from the Lapstone Structural Complex. Earth Surface Processes and Landforms. doi: 10.1002/esp.3535
Tectonic uplift has a strong influence on the intensity of gully development as well.
When evaluating satellite data in order to carry out lineament analysis you will get an overview of the tectonic pattern. The comparison of the lineament maps and, then, the gully arrangement will help to verify the tectonic influence.