There's been a surge in earthquakes in the U.S. over the last few years. In Texas, there are 10 times the number of earthquakes now than just a few years ago.
Scientists say it's likely linked to the boom in oil and gas activity, meaning that people who never felt the ground shake are starting to.
Here's how Pat Jones of Snyder, Texas, describes the earthquake that struck her town in 2010: "It just sounded like some car hit the back of our house. We got up and checked around and we didn't see anything or hear anything else."
In 2012 in Alvaredo, Craig Bender called 911 about a quake and told the operator, "There was an explosion-type sound somewhere which kind of concerns me, but I haven't seen anything burning anywhere."
In a public forum with state oil and gas regulators, Greg Morrison described the feeling of a quake in Reno as "a semi truck hitting your house with a bomb going off."
Outside Texas, people are hearing those booms as well, often in states where there's been an upsurge in drilling and the use of disposal wells to store drilling waste. Scientists have linked those wells to quakes, and some quakes can get loud.