On Sept. 19, 2017, the U.S. Geological Survey recorded at least 19 earthquakes across the world. Most notable being the magnitude 7.1 earthquake that shook Mexico and caused fatalities leading into the hundreds.
In reality, earthquakes happen almost every day. Magnitude 2 and smaller earthquakes occur several hundred times a day worldwide, while major earthquakes (magnitude 7) occur once a month. “Great earthquakes” (magnitude 8 and higher) occur about once per year.
The earth is made up of twelve major tectonic plates that float on heated magma and constantly move against one another. Earthquakes happen mostly in areas where two plates are in close proximity to each other. For example, the popular San Andreas Fault serves as a plate boundary (a place where two tectonic plates meet).
Approximately 80% of the world’s earthquakes strike along the “Ring of Fire” (via Hongfeng Yang, a seismologist at the Chinese University of Hong Kong), an area of seismic activity. It is a 25,000-mile (40,000-kilometer) area that stretches through many plates including the Pacific Plate, the Philippine Sea Plate, and the Cocos and Nazca Plates — all lining the Pacific Ocean. This means that people are more at risk of experiencing an earthquake if they are in Chile, Japan, the U.S. West Coast, Mexico, and other islands in the Pacific Ocean.
The impacts of tectonic plates are typically gradual, and not very noticeable, but stress can build up between plates after a while. When this stress is released abruptly, it sends massive vibrations, or seismic waves, up to the surface.
The magnitude of an earthquake is measured using the Richter Scale. The Richter Scale runs from zero to ten, with ten being the strongest. Every whole number that increases means ten times more strength. A magnitude of three to five is considered minor, five through seven is considered strong, and seven through eight is considered great.
On average, 10,000 people die due to earthquakes each year. Collapsing buildings have caused the most fatalities during earthquakes, and destruction is often a mix of fires, floods, and even tsunamis.
The earth beneath us isn’t as stable as we think. Earthquakes will constantly keep us on edge because they are unpredictable, but scientists and engineers are taking the necessary steps to compile the maximum amount of prevention. Right now, we can only estimate the probability that earthquakes will occur, but scientists are crunching data in order to possibly be able to predict earthquakes in the future.