The 1979 oil crisis, also known as the 1979 Oil Shock or Second Oil Crisis, was an energy crisis caused by a drop in oil production in the wake of the Iranian Revolution. Although the global oil supply only decreased by approximately four percent, the oil markets' reaction raised the price of crude oil drastically over the next 12 months, more than doubling it to $39.50 per barrel ($248/m3). The sudden increase in price was connected with fuel shortages and long lines at gas stations similar to the 1973 oil crisis.