Tsunamis in Japan
Tsunamis and Earthquakes
Japan is located in the Pacific Ring of Fire, which is "an area of high tectonic activity" which causes around 90% of the world's earthquakes (Finlayson, 2019). Japan is also located in a subduction zone which is, "a spot where two of the planet's tectonic plates collide and one dives, or subducts, beneath the other" which causes further high seismic activity (Dhar & Oskin, 2022). This tectonic/seismic activity, or more commonly known as, earthquakes, cause a disturbance in the ocean, further causing "high sea waves" or tsunamis (Finlayson, 2019). Even though tsunamis mostly occur through earthquakes, they can also take place with landslides, volcanic eruption underwater, and/or meteor impacts (Finlayson, 2019).
Effects of Tsunamis
The height and devastation of a tsunami depends on the magnitude of the earthquake that caused it. Scientists and Seismologists use different things to measure how "big" an earthquake was, including the Richter scale, Modified Mercalli Intensity Scale (MMIS), and a "Did You Feel It?" questionnaire to see how far the earthquake reached (Seismic Hazards Program, n.d.). The Richter scale measures the magnitude or "the energy released by an earthquake" while the MMIS measures the intensity or to what scale did the earthquake effect its surroundings (Wood & Neumann, 1931). The higher the number for either the Richter scale or MMIS, the more devastating it is. The same can be said for "Did You Feel It?" as the further out from the original earthquake people could feel it, the higher the magnitude and/or the intensity.
Small earthquakes occur everyday and those living close to a coastal area see small tsunamis as well. Since they are so small the waves dissipate before they reach the shore and the earthquakes just shake the ground a little for a small duration of time. In extreme cases, tsunamis can wash away many infrastructures and earthquakes last a long time leading to disastrous effects. This includes, as stated previously, the destruction of many buildings, such as homes, hospitals, stores, etc. (SMS Tsunami Warning, n.d.). Tsunamis also consume thousands of lives as there is little-to-no warning before a tsunami hits leaving those with no time to plan or evacuate their homes. In going with this, the risk for disease/infection increases with tsunamis as the waters are contaminated and with the destruction of hospitals/health centers, there aren't many places to treat these infections. Even after the waves of a tsunami have ended, the trash and debris of buildings leaves those who live in these affected areas rebuilding and cleaning the surrounding areas for years.
The Tōhoku-oki Earthquake
On March 11, 2011, an earthquake with a magnitude of 9.1 struck 45 miles east of Tōhoku, Japan on the seafloor and lasted roughly six minutes (Oskin, 2022). The waves reached to a height of around 40 meters (130 feet) and flooded an approximated area of 561 sq. kilometers (217 sq. miles). "More than 120,00 buildings were destroyed, 278,000 were half-destroyed and 726,000 were partially destroyed" which costed Japan about 17 trillion yen ($200 billion USD). Along with the almost one million buildings affected by the tsunami, the "Fukushima Daiichi Nuclear Power Plant" had a "cooling system failure" which "resulted in a level-7 nuclear meltdown and release[d]... radioactive materials" (Oskin, 2022). A level-7 nuclear disaster is the highest disaster that can occur and there have only been two that have occurred in history, one being in Fukushima, Japan, the other in Chernobyl, Ukraine (IEC, n.d.). Small amounts of chemicals were "detected along the North American coast offshore Canada and California" in 2014 and 2015 (Oskin, 2022). Due to the radiation and destruction of many different infrastructures, as of December 2021, the confirmed number of deaths caused by this tsunami reached around 19,700 people.