A disruption of market equilibrium (that is, a market adjustment) caused by a change in a demand determinant (and a shift of the demand curve) or a change in a supply determinant (and a shift of the supply curve). A market shock can take one of four forms--an demand increase, demand decrease, supply increase, or supply decrease. An increase is seen as a rightward shift of either curve and results in an increase in equilibrium quantity. A decrease is a leftward shift of either curve and results in a decrease in equilibrium quantity. However, a change in demand results in price and quantity to change in the same direction, while a change in supply causes equilibrium price to move the opposite direction as quantity.