Undulation in stratified rocks refers to waves or undulations that form across surfaces in layers of stacked rock strata over time. These undulations are caused by compression or tension resulting from tectonic plate movement below the Earth’s surface. As plates shift and collide with one another they push up against each other creating pressure that results in compaction in certain areas while warping others into an uneven surface patterned with ridges and dips along its length. A fracture is a break between two pieces of rock within a single formation that allows for relative motion between them due to natural forces such as tectonic activity below ground level. Fractures come about due to both physical stress acting upon individual formations as well as chemical disintegration caused by fluids passing through fissures found within them over long periods of time; both processes work together to create fractures allowing for greater mobility amongst otherwise rigidly connected blocks . The size, type and arrangement of fractures vary depending on several factors including lithology (rock type), temperature & pressure changes throughout geological history - all playing a part in determining how fracturing will develop over hundreds thousands years.. Fractures can be further classified according to different characteristics such as planar (flat) or irregular (curved). Each classification has its own unique properties ranging from those that permit only slight displacement among adjoining parts (planar) through those characterized by major displacement along fault lines (irregular). Flat fractures occur at nearly right angles with respect to existing bedding planes while curved fractures may feature more complex geometries where multiple directions may intersect making it difficult to predict possible displacements taking place along them.. Additionally some types fractures may be linked together forming networks which allow for larger scale movements than what would normally be present if singular isolated fractures were encountered instead - greatly increasing potential strain levels experienced within surrounding regions especially during seismic episodes where entire sections may move suddenly causing powerful shocks throughout nearby zones.. Overall understanding the presence, geometry orientation & extent offractures help geologists gain insight into natural processes occurring deep beneath our feet giving them vital clues regarding past events taking place millions years ago helping us better prepare ourselves for unexpected events coming our way now..