Question

1. Risk of earthquake due to human activities like extensive mining, underground nuclear testing etc.

Answer 1

There are several different types of earthquakes, each with their own specific causes. Some are triggered by natural forces. Tectonic earthquakes, for example, occur when the plates in the outermost layer of the Earth (called the crust) suddenly move against each other and release energy, causing the Earth to shake.

 You might be surprised to learn that human activity can cause earthquakes. When large reservoirs (the Hoover Dam, for example) are filled with water, the resulting pressure can shift nearby rock, causing an earthquake. These earthquakes usually are not serious enough to cause extensive damage. Injecting liquids into deep underground wells can also trigger earthquakes.

Nuclear testing that involves underground explosions is another example of human activity that can set off earthquakes. These large explosions can dislodge rock and affect plate movement. Similarly, removing large quantities of rock for a mine excavation can cause shifts in tectonic plates, resulting in an earthquake.

Human activities that cause global warming may also be linked to earthquakes. Some scientists believe that global warming may cause earthquakes in the future. As rising global temperatures melt ice sheets and glaciers, the Earth's crust may rebound due to the absence of the ice's massive weight. That in turn can affect plate movement and faults, and cause earthquakes.