Earthquakes are generally associated with faults. Faults are fractures in the Earth`s crust where there has been movement. When the stress on the rocks along the fault exceeds their strength, the rocks rupture and release energy, causing an earthquake. Faults can be categorized into three main types: normal, reverse, and strike-slip.

Normal faults occur when the hanging wall moves downward relative to the footwall due to tensional forces. Reverse faults occur when the hanging wall moves upward relative to the footwall due to compressional forces. Strike-slip faults occur when the rocks on either side of the fault move horizontally past each other due to shear forces.

While joints, folds, and schistosity are all geological features, they are not directly associated with the occurrence of earthquakes. Joints are cracks in rocks, folds represent bends and waves in rock layers, and schistosity refers to the parallel alignment of minerals in metamorphic rocks.

Therefore, the correct answer is option 2 - Faults.