The Nasa Space Place defines a tsunami as a large wave caused by the movements of the earth's outer layers, or crusts, leading to the movement of ocean water. The word tsunami is driven by the Japanese description of "harbor wave." Earthquakes or volcanoes in the ocean can cause tsunamis. When these occurrences occur in the ocean, they cause large displacement of water at equivalent speed and may lead to serious casualties.
Please take note that at the shores, the ocean is shallower; therefore, as the waves move closer to it, they will accelerate in speed and become taller. Tsunamis differ in speed and height as well as the force they exact. NASA, an American scientific body, uses the Multi-angle Imaging Spectroradiometer to watch tsunamis and warn the public of the impending danger. Different countries have specific budgets for emergency and disaster response that Tsunamis may cause. Here are the 10 worst tsunamis of all time.
How to Determine the Severity of a Tsunami?
Several factors are used when calculating how worse or more destructive a tsunami is. They include:
- The speed of its waves.
- The height of the tsunami. The lower it reaches the shores, the higher the tsunami will likely be.
- The magnitude of the earthquake.
- If caused by other causes other than earthquakes, we also look at how long the occurrences took place. For example, if it is a volcano, how many ruptures occur?
- The number of casualties. The number can also be defined by the time it takes place. In the evening, shore activities are high hence the possibility of recording very higher numbers of casualties.
- The budget amount to be incurred to recover the damages.
However, we must appreciate that for tsunamis that happened before the digital era; their actual measurements may not be exact, nor the reporting of their damages.
10. Ise Bay, Japan-January 18, 1586 (7.9)
The Ise Bay tsunami is one of the oldest tsunamis to be recorded. A 7.9 magnitude earthquake caused it, and its waves went as high as 6 meters. The waves were recorded at 3 meters high at the Ise bay. The epicenter of the earthquake was Honshu's Chubu region. 8,000 people died, and the tsunami destroyed 10,0000 houses. The most affected areas were Toyama, Kyoto, Hyogo, Osaka, Mie, Nara, Fukui, Gifu, Shizuoka, and Ishikawa. The details of this tsunami remain scanty because it took place during the Sengoku period. No known cause of the earthquake exists, but geologists have attributed it to the possible splitting of fault lines. The impact was that it caused large landslides in the northern part of the damage zone. It also led to fires at Ogaki castle. It also caused soil liquefaction that led to the vanishing of small islands near the Kiso River.
9. Ryukyu Islands, Japan-April 24, 1771 (7.4)
At around 0800 hours of the material day, the 7.4 magnitude Yaeyama Great Earthquake hit the Ryukyu Kingdom (currently known as Okinawa, Japan). It caused the death of more than 11,000 people on both the Ishigaki and Miyako Islands. The University of the Ryukyu reports that a fault caused the earthquake in the eastern part of Ishigaki. The earthquake's depth was rated at 6 kilometers, and its trench lay between the Eurasian and Philippine Sea plates. More than 2,000 homes were destroyed. The tsunami destroyed cultural fields, leading to a famine that hit the region for more than 80 years; when you visit the coasts of Yaeyema and Miyako, you shall come across huger builders who are said to be left behind by the tsunami.
8. Northern Chile-August 13, 1868 (8.5)
At around 2130 hours, an 8,5-earthquake hit the Arica part of Peru on August 13, 1868. The earthquake was also felt in Hawaii, Japan, New Zealand, and Australia. The earthquake was experienced between the South American and Nazca plates. It was attributed to thrust-faulting that was caused as a result of the subdivision of the two plates.
Some parts of Peru were almost destroyed, with areas such as Tacna, Arica, Mollendo, Ilo, and Torata being recorded. There were 25,000 casualties reported from the incident. The tsunami was so powerful that three ships that had been anchored on the coastal shores of Peru were driven away and destroyed. In Hawaii, the tsunami washed away the Waihi River bridge, and in New Zealand, it caused unimaginable damage to the Chatham Islands and washed away 20 people.
7. Sanriku, Japan-June 15, 1896 (8.5)
The tsunami was caused by an earthquake estimated at a magnitude of 7.6, and it took place on the Sanriku coast of Japan. The highest waves were reported at Shirahama, where they reached a height of 38.2 meters. More than 11,000 homes were destroyed, and more than 22,000 people were killed. Reports also indicated that there was a corresponding tsunami on the shores of the Eastern part of the Chinese coast, which led to the death of more than 4,000 people and destroyed local crops extensively.
However, it is important to note that no authority explicitly states that the same earthquake caused the two. Experts attribute the severe damages caused by the tsunami to the fact that it coincided with the high evening tides. In addition, at the same time when fishing and recreational activities are high alongside the oceans.
6. Nankaido, Japan -October 28, 1707(8.7)
The Risklayer attributes a magnitude of 8.7 to the earthquake that caused this tsunami. The details on the depth are scanty, the height was 25 meters, and it crushed the shores of Kyushu, Honshu, and Shikoku with some parts of Osaka. The tsunami swept more than 30,000 buildings and caused the death of more than 30,000 people. The tsunami occurred around 3 pm and 4 pm on the same day, extending several kilometers to places such as Kochi. Notably, Nankaido has experienced more than ten deadly tsunamis. Most of them have been caused by magnitudes between 7.9 and 8.7.
5. Enshunada Sea, Japan-September 20, 1498 (8.3)
The Australia Geographic reported that an earthquake of almost 8.3 magnitudes caused the tsunami. It occurred on the Mikawa, Kii, Surugu, Sagami, and Izu coasts. A split that had separated Lake Harama and the tsunami breached the sea. In addition, it led to the death of more than 31,000 people, and more than 1,000 homes were swept away. It cost between $5 to $24 million to repair the damages caused by the tsunami.
4. Krakatau, Indonesia-August 27, 1883 (46 meters high)
The 1880s witnessed some of the most devastating earthquakes in the world, with one of them being the Krakatoa. The explosion took almost three months before it cooled down, from May 20 to August 27. In the process, more than 70% of Krakatoa's areas were destroyed. The explosions could be heard 1900 miles away in Western Australia. The tsunami caused more than 36,000 deaths. So terrifying was that ships on the waters of South Africa reported disturbance in their stability. At the highest points, heights of almost 150 feet were recorded (46 meters).
3. Lisbon Tsunami, November 1, 1755(8.5)
Though it happened when the scientific world had not developed enough on how to take control and measurement of tsunamis, the impacts of this one is reflected in modern society. When the earthquake hit the waters of Lisbon, Portugal, it sparked fires and serious losses of life. The tsunami was between 6 and 20 meters high, depending on the shallowness of the ocean. Waves at far cities such as Carlisle Bay were affected though they only measured 1.5 meters higher.
According to Ocean Info, the tsunami caused the deaths of up to 50,000 people. It was so devastating that it inspired some European philosophers to write and speculate about future occurrences of the same nature. Despite that, the scholars were only imaginatively writing, which led to seismology's emergence, which helped fuel other studies on tsunamis.
2. North Pacific, Japan -March 11, 2011 (9.0)
In 2011 Japan experienced one of the fastest tsunamis traveling 800 kilometers per hour. The tsunami was 10 meters high and largely affected Japan's east coast; in the end, it killed 18,000 people. An earthquake of 9.0 magnitude spawned the tsunami. Experts reported that it reached up to 24.4 kilometers in depth. More than 452,000 people were displaced, they had to move to shelters, and dozens of thousands of homes were destroyed. The shaking caused by the tsunami affected the stability of the Fukushima Daiichi nuclear plant, forcing it to start leaking radioactive steam. The tsunami caused damages amounting to almost $235 billion, with estimations that the Japanese economy would take almost five years to recover from the same.
1. Sumatra, Indonesia-December 26, 2004 (9.1)
The tsunami was caused by a 9.1 earthquake that took off the Sumatra coast and was estimated to be 30 kilometers. Experts estimated that it caused damage of $10 billion; more than 230,000 people lost their lives, and many were displaced. The Faultline of the earthquake was reported to be about 1300 kilometers long. It vertically displaced the sea floor by quantifiable meters along that length. It was 50 meters tall and reached up to 5 kilometers into the mainland up to areas such as Meubolah, Sumatra. This is one of the tsunamis highly recorded, with far-reaching measurements being taken in the U.K, U.S, and America.
The Financial Implications of Tsunamis in Different Parts of the World
According to the Relief Web, the United Nations Office for Disaster Risk Reduction (UNISDR) reported that by November 2, 2018, tsunamis had contributed to a significant loss of property and life. The body reported that between 1998 to 2017, tsunamis had caused 251,770 deaths and a combined loss of $661.5 billion with the earthquakes. Tsunami events in Japan would even go to the extent of causing $228 billion in losses and approximately 19,000 deaths in a single incident in 2011. These occurrences made the declaration of November 5 as World Tsunami Awareness Day. Some countries, such as Indonesia, are still struggling to recover their economies due to tsunamis that hit them on September 2018. The overall impact is that this is a serious humanitarian crisis.
Mitigation of Tsunamis
As illustrated above, tsunamis can result in loss of life and destruction of properties. To minimize its impacts, there are several mitigating factors that we can put in place to minimize their impacts.
- Each country that borders a larger water body mass must develop a strategic plan for managing tsunamis and, where possible, allocate independent budgets.
- Creating public awareness. Governments can achieve this by training community leaders on simple disaster management techniques and first aid skills.
- Creation and sensitizing the public on evacuation roots.
- Revise housing design to ensure that they can withstand the pressure caused by tsunamis or, at best, cause the least damage.
- Moving critical public assets from tsunami zones. For example, governments can do stadiums and other social institutions such as churches away from those areas.
- Establishment of fully funded sections within the disaster management units responsible for the mitigation of tsunamis only.
- Installation of public warning systems that the relevant authority can convey through text messages or public announcement addresses in populated areas.
- Investing in prediction technology. The more a given community can predict a tsunami, the more the chances of preparing and minimizing casualties.
Governments must admit that tsunamis are serious threats to human life, and their response cannot be left in the hands of a single institution. Inter-departmental cooperation is required for their success. International bodies such as the United Nations should be at the front of demanding that nations draft policies and guidelines on responding to tsunamis. Affected nations must be availed of the necessary aid.
Despite the atrocities that came with tsunamis, we must also appreciate that ocean and sea waters are lucrative areas in which we can relax or invest. They give some of the most comforting experiences in human life. Most of the tsunamis discussed herein are caused by earthquakes, which implies that if the world can accurately predict earthquakes, then the chances of doing the same with tsunamis are high. Notably, the world must appreciate that these are natural calamities that it cannot do away with but only choose to mitigate.
Written by Dana Hanson
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