Earthquakes occur in two ways: as a result of tectonic plates colliding, or because of volcanic activity. The shock waves that result from nuclear weapons, along with other man-made explosions are quite similar, but earthquakes occur from natural origins. The movement of tectonic plates can spur an earthquake, launching a series of events. The theory of plate tectonics involves the crust of the Earth, which is composed of many plates that are on the Mantle. These plates have the ability to move slowly, meaning they can drift towards one another, slide past one another, or drift away from each other. Earthquakes occur when plates collide or slide by another (Coffey, 1).
Major earthquakes can be attributed to a preview of changed activity. This may involve frequent minor shocks as the rocks initiate movement, which is referred to as foreshocks. Alternatively, this may involve a time period of shocks that are less frequent, as the two rock masses join, thus locking together. Once the main shock has occurred, additional movements may occur, which are referred to as aftershocks. Aftershocks occur primarily because the rock masses are settling into new and different locations. Aftershocks also present additional complications, as rescue services may be hindered by the activity of aftershocks that may bring down buildings that were originally affected by the main shock (Morris, 30).
The other cause of earthquakes is attributed to volcano activity, which is far less common than earthquakes caused by tectonic plates (Bolt, 905). Volcanic earthquakes are brought on by the explosive eruption of a volcano. When a volcano erupts, the earthquake activities that follow usually occur in an area from 16 to 32 km around the base of the volcano (Coffey, 1).
Volcanoes that face a greater risk of exploding are those that generate acidic lava. Acidic lava cools and sets rapidly when it meets the air. As a result, this chokes the vent of the volcano, thus blocking pressure from being released. The blockage can only be removed by a continual increasing of pressure, thus forcing an explosion outward in an eruption. Volcanoes typically explode where it is most weak, so often an upward motion will not always occur (Sinvahl, 134). Astronomically high levels of pressure can create an earthquake with a sizeable magnitude. In fact, the shock waves generated by an earthquake often create a series of tsunami in some cases (Sinvahl, 147).
In the last decade alone, there have been a number of severe earthquakes that have brought heavy destruction to many populations around the world. On April 25, 2015, over eight thousand people were killed in a 7.8 magnitude earthquake in Nepal. This triggered an avalanche on Mount Everest, killing over a dozen individuals. Deaths were also reported in Bangladesh, India, and Tibet. Only a couple weeks later, another very strong earthquake occurred again in Nepal, making this year the most fatal disaster on record in the country (Lackey, 1).
Back in August of 2014, 700 were killed in China following a massive earthquake with a magnitude of 6.2. The deaths occurred primarily in Wepping: a mountainous and remote region of China. Over twelve thousand homes crumbled, with at least two thousand people injured. The epicenter of the quake was in Ludian County, in the city of Zhaotong: a deadly region for earthquakes (Lackey, 1).
On September 24, 2013, another destructive earthquake occurred in Pakistan, killing about 825 people. With a magnitude of 7.7, the earthquake occurred in the rural, southwestern region of Baluchistan. In the nearby city of Dalbadi, three hundred and fifty homes were utterly obliterated (Lackey, 1). On March 11, 2011, another notorious earthquake occurred in Japan. 18,000 were reported dead or missing, as the earthquake’s magnitude was reported at 9.0, striking just near the coast of Japan. This also brought on a tsunami that crested at ninety feet high. Four years following this event, there are over twenty six hundred individuals that are still missing. The earthquake is responsible for washing away communities and entire villages all along the country’s northeast coast. This was, undoubtedly, the largest earthquake to ever occur in Japan (Lackey, 1).
Five years ago in Chile on February 27th, the 8.8 magnitude earthquake killed at least seven hundred people. This earthquake occurred on the coast of Chile, affecting over one and a half million people and damaging at least 500,000 homes. The earthquake also triggered a giant tsunami that killed many on a smaller Chilean island. Also in 2010, a horrific earthquake occurred in Haiti on January 12th. This earthquake had a magnitude of 7.0, and affected primarily Port-au-Prince: the Haitian capital. This disaster claimed well over 300,000 people, leaving over a million people homeless. To this day, the tent city from the disaster still exists (Lackey, 1).
In summary, earthquakes are caused primarily by either tectonic plate activity, or by volcanic activity. Often, earthquakes can also produce tsunamis, which can be just as fatal following an earthquake. There have been a series of earthquakes in the last several years alone, claiming hundreds of thousands of lives, and demonstrating to the world just how powerful Mother Nature can be.
Bolt, Bruce. “Earthquakes and Earth Structure.” Nature (1964): 905-06. Print.
Coffey, Jerry. “How Earthquakes Happen.” Universe Today. 5 Dec. 2010. Web. 26 Oct. 2015.
Lackey, Katharine. “The World’s Deadliest Earthquakes in past Decade.” USA Today. Gannett, 16 Sept. 2015. Web. 26 Oct. 2015.
Morris, Neil. Earthquakes. New York: Crabtree Pub., 1998. Print.
Sinvhal, Amita. Understanding Earthquake Disasters. New York, N.Y.: McGraw-Hill Education LLC., 2010. Print.