The world is full of natural disasters such as earthquakes, hurricanes, and tornadoes. However, most of the time, we are not aware of them. When they do occur, the damage is often very extensive. This is why it is important to be able to predict them. It is also important to have an alarm system in place in case of an earthquake. The most common alarm systems have a loud siren that is placed near the door. If you are in a building that is built to withstand earthquakes, you can place the siren in a safe location. This is the most common alarm system that is used in the world.