Natural disasters in Japan

Many types of natural disasters occur in Japan such as tsunamis, floods, typhoons, earthquakes, cyclones, and volcanic eruptions, leading to periodic disruptions in economic and social activities.

The country has gone through thousands of years of natural disasters,[1] affecting and shaping Japanese culture, economy, development, and social life.

A mudslide, or mudflow, occurs when rocks, sand, and earth are loosened and fall from hills and mountains due to earthquake, rain or snow.

On September 14, 1984, the Otaki earthquake (magnitude 6.8) in Nagano Prefecture, Japan, caused a major mudslide on the south face of Mount Ontake, which reached speeds of 80~100 km/h.

[7] Heavy rain over several days prior to the quake contributed to causing the mudslide, known as "Ontake Kuzure," which took the lives of 29 people.

[8] In September 2011, Tropical Storm Talas (2011), which formed and was named on August 25, made landfall over Japan, bringing heavy rain to the mountainous Kii Peninsula, and causing a mudslide, called "Shinsohokai," in Wakayama and Nara.

Rising oceans are also making the Tokyo metropolitan area, home to 38 million people, vulnerable to storm surges.

[11] Years of pumping up groundwater have caused some parts of the city to sink nearly 5 meters over the past century.

Given population growth in the Kanto Plain, where Japan's second-longest river, the Tone, is located, these shares are likely higher today.

Water pushed to shore by strong winds or typhoons and coinciding with tide can cause significant sea level rise.

The first form of flood management dates back to the 4th century when the Manda-no-tsutsumi (Manda Levee) was built at the Yodo River.

The length of a river channel is shortened by straightening bends, so that flood water can flow through it quickly.