Some scientists have traced the increase in earthquakes, especially in areas not known for the presence of fault lines or past seismic (地震的) activity, to human actions. The idea of humans causing earthquakes may seem strange at first. After all, you can run around your backyard and jump up and down as you want, and the ground isn't going to start shaking. However, scientists have identified a variety of large scale human activities that can result in earthquakes.
Scientists have confirmed over 700 places where human activities have caused earthquakes over the last century. While many human-related earthquakes are mild and don't cause much damage, some of them can be serious and dangerous. In fact, scientists believe human activity has caused earthquakes with magnitudes as high as 7. 9 on the Richter scale.
Scientists believe most human-related earthquakes are the result of mining. As companies drill deeper and deeper below Earth's surface to get natural resources, holes left behind can cause instability that leads to collapses that cause earthquakes. Another human activity leading to earthquakes is fracking (水力压裂) for oil and gas, including the high pressure waste water processing that usually goes with fracking. In this process, water, sand and chemicals are pressed underground under high pressure to break rocks to release natural resources.
Building large dams can also cause earthquakes. For example, about 80, 000 people died in China in 2008 as a result of a 7. 9-magnitude earthquake caused by 320 million tons of water that had been collected in the Zipingpu Reservoir after a large dam was built over a known fault line.
These aren't the only human activities that can result in earthquakes, though. Scientists point out that earthquakes can also be caused by other human activities, such as construction of skyscrapers and nuclear explosions.
