If a plate with oceanic lithosphere meets another plate, the dense oceanic lithosphere dives beneath the other plate and sinks into the mantle: this process is called subduction. The sinking oceanic lithosphere drags the rest of the tectonic plate: this is the main cause of plate motion.
You may notice a decrease in symptoms during the build-up phase, but it may take as long as 12 months on the maintenance dose to notice an improvement. If allergy shots are successful, maintenance treatment is generally continued for three to five years.
You gradually receive more of the allergen in the shots. After about 4 to 6 months of weekly shots, you are usually getting the best amount of allergen in the shot. This is called the maintenance dose. When you reach the maintenance dose, you get the same dose in shots every 2 to 4 weeks for the next 4 to 6 months.