[ 107 ] Earth and Space Science GED ® TEST SCIENCE FLASH REVIEW • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • Refer to the following passage to answer the next three questions. Billions of barrels of oil are believed to be locked in soft, finely stratified sedimentary shale formations throughout the United States. Natural gas and oil companies are hard at work freeing these resources. Hydraulic fracturing, more commonly referred to as fracking, is a drilling process in which millions of gallons of fresh water, sand, and chemicals are injected under high pressure into a well. This cracks the existing rock and releases the natural gas and oil. The fluids used in hydraulic fracturing, and the wastewater that comes back up the well, need to be disposed of. The safest, most cost-efficient method of disposal involves injecting the fluids into disposal wells thousands of feet underground. The wells are encased in layers of concrete and usually store the waste from several different wells. Each holds about 4.5 million gallons of chemical-laced water. Sometimes, injections of waste into these wells cause earthquakes. These earthquakes occur as crevices, previously containing oil, are filled with water. The resulting pressure change needed to push the water underground can trigger a slip in a nearby fault line. Based on the information in the passage, where are the natural gas deposits that are targeted by hydraulic fracturing? A. underneath sand B. in shale formations C. inside concrete wells D. below the water table