The process of hydraulic fracturing has unlocked an unprecedented amount of oil and gas in the United States. Hydrocarbons are not the only output from this process, though, as billions of barrels of "produced" water are extracted and subsequently pumped back underground. This process of injecting produced water into disposal wells has been causally linked to the rise in earthquakes. Here I show how the amount of earthquakes in Oklahoma are positively linked to the price of oil, and further find that the decrease in earthquake activity in Oklahoma is due to both the drop in oil prices and the regulatory directives of regional authorities. The estimated impact of the various shut-in policies have been small compared to the reduction in earthquakes due to the broad price decline, though. I find that the drop in oil prices that began in mid-2014 led to as large of a reduction in earthquakes as the combined effect of new policies that started in March of 2015.

Recent legislation intended to increase the use of renewable energy sources and lower the amount of carbon dioxide emissions from energy has changed the structure of energy markets. The effect of these policies on carbon-intensive fuel sources is rather obvious. For natural gas, though, the effect is not immediately clear. This letter uses a structural model of natural gas demand to uncover whether these policies have led to increased demand because natural gas is a relatively clean source of energy that couples well with renewables or if these policies have crowded out natural gas on net.