living with natural disasters

Why do earthquakes occur?

Do you know why the earthquake occurs?
The surface is covered with a 10km thick "plate", which floats in a layer called the mantle.Also, these plates are moving a few cm speed a year.
Four plates, the ocean and land plates, touch each other near Japan. The oceanic plate on the Pacific Ocean side, which moves at a rate of several tens of centimeters per year, subducts under the continental plate, which is unable to withstand the strain and causes earthquakes.

Area where earthquakes occur

Earthquakes do not occur everywhere in the world. Earthquakes often occur in areas called orogenic belts. Japan is located in a region called the Pacific Rim orogenic belt, and because it has four plates, it is prone to earthquakes. Japan is located in the Pacific Rim orogen, and has four tectonic plates, making it prone to earthquakes.

supplement

In addition to the Pacific Rim orogen, there are other orogens such as the Alps and Himalayas.
This orogen is located from Europe to South Asia. Recently, there was a huge Turkey-Syria earthquake (magnitude 7.8).


About the Nankai Trough mega-earthquake

Nankai Trough mega-earthquakes occur when the Philippine Sea Plate is subducting downward from the south by several centimeters per year beneath the continental plate of the Japanese archipelago, and when the strain reaches its limit and jumps up, a mega-earthquake occurs.

As of January 24, 2020, the government's Earthquake Research Committee estimates that the probability of a magnitude 8 to 9 class earthquake occurring within 30 years is 70% to 80%.

However, on January 13, 2022, the probability of a major earthquake occurring within 40 years was raised to 90%.

It is estimated that up to 30 prefectures from the Kanto region to the Kyushu region were affected, with approximately 320,000 deaths and 2.38 million buildings destroyed or destroyed.
Additionally, it is estimated that up to 9.5 million people will be forced to live in evacuation centers or with relatives in the week following the earthquake.
it is estimated that 96 million meals will be in short supply due to infrastructure damage.

What is the possible damage caused by the Nankai Trough?

Estimated death toll from Nankai Trough damage exceeds 320,000

The government says that when the Nankai Trough occurs, a large earthquake with a seismic intensity of 7 and a large tsunami exceeding 10 meters will hit the coast. In the worst case scenario, the death toll will exceed 320,000 people and the economic damage will reac 220 trillion yen.

Damage caused by the Nankai Trough

Chugoku region

In the Chugoku region, damage is expected to occur with a seismic intensity of 5-upper to 6-upper, with a total of 2,300 deaths and 25,500 injuries in Okayama, Hiroshima, and Yamaguchi prefectures.

Kyushu region

The Kyushu region is expected to experience damage from a seismic intensity of 5 lower to 7, with a total of 57,550 buildings damaged, most of which will be destroyed by fire, tsunami, shaking, etc.

Shikoku region

The Shikoku region is expected to experience damage with a seismic intensity of 6-upper to 7, with a total of 214,300 buildings damaged in the Shikoku region.
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