What geological processes are associate with droughts?

Answer 1

If wells are used in the area to supply water, the lack of replacement water will cause problems. The loss of water in the soil will effect the chemical make-up of the soil.

Even if wells are not used to supply water, the water will evaporate near the surface of the soil.

Answer 2

If we define a drought as a period of lower than average rainfall, then geological processes are not related to droughts. Geological forces cause change which happens too slowly for the climate changes brought about by them to be regarded as unusual to us. Mountains, such as those at the west edge of North Africa, or the Himalayas cause the winds blowing across them to rise, which causes the moisture in the air to fall as precipitation on the windward side of the mountain. The air which descends the other side of the mountain will be very dry, resulting in a desert. But a desert is normally dry, so the dryness of a desert is not considered a drought.