Japan is regularly affected by natural disasters, with the country being in the Ring of Fire. Two out of the five most expensive natural disasters in recent history have occurred in Japan, in 1995 (~6,500 deaths) and 2011 (~20,000 deaths) – the latter of which had also triggered the Fukushima Daiichi nuclear disaster. The most devastating recorded natural disaster to affect Japan by death toll was the 1923 Great Kantō earthquake, which killed ~105,000 and a further ~6,000 due to the Kantō Massacre in its immediate aftermath.

Japan has also been the site of some of the 10 worst natural disasters of the 21st century. 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, affecting and shaping Japanese culture, economy, development, and social life.

Volcanic eruptions

Many volcanic eruptions have taken place in Japan.

List of major volcanic eruptions YearVolcanoDeath tollNote1640Hokkaido Komagatakeabout 7001707Mount FujiNone1721Mount Asama151741Oshima (Hokkaido)1,4671779Sakurajima1531783Mount Asama1,1511785Aogashima130～1401792Mount Unzenabout 15,0001822Mount Usu1031888Mount Bandai461〜4771900Mount Adatara721902Izu Torishima1251914Sakurajima58～591926Mount Tokachi1441940Miyakejima111952Bayonnaise Rocks311958Mount Aso121991Mount Unzen432014Mount Ontake63

VEI-7 Volcanic eruptions

There are three VEI-7 volcanoes in Japan. These are the Aira Caldera, Kikai Caldera and Aso Caldera.

Mount Aso is the largest active volcano in Japan. Mount Aso had four eruptions 300,000 to 90,000 years ago. It emitted huge amounts of volcanic ash that covered all of Kyushu and up to Yamaguchi Prefecture.

+ VEI 7 eruptions have happened in the following locations of Japan.NameZoneLocationEvent / notesYears ago before 1950 (Approx.)Ejecta volume (Approx.) Kikai Caldera Japan, Ryukyu Islands Akahoya eruption 5,300 BC 7,300 170 km3 Aira Caldera Japan, Kyūshū Aira-Tanzawa ash 30,000 450 km3 Aso Caldera Japan, Kyūshū Aso-4 pyroclastic flow 90,000 600 km3 Mount Aso Japan, Kyūshū Four large eruptions between 300,000 and 90,000 years ago. 300,000 600 km3

Earthquakes Japan has had a long history of earthquake catastrophes and seismic activity, the most deadly of which was the 1923 Great Kantō earthquake. In the 21st century, the most severe earthquake that occurred was the 2011 Tohoku earthquake and tsunami.

List of recent earthquakes in Japan

Location Date Estimated deaths Hokkaido earthquake 1993, 12 July 202 Offshore Sanriku earthquake 1994, 28 December 3 Kobe earthquake 1995, 17 January 6,434 Ryukyu Islands earthquake 1998, 4 May 0 Geiyo earthquake 2001, 24 March 2 Hokkaido earthquake 2003, 26 September 1 Chuetsu earthquake 2004, 23 October 40 Fukuoka earthquake 2005, 20 March 1 Miyagi earthquake 2005, 16 August 0 Kuril Islands earthquake 2006, 15 November 0 Kuril Islands earthquake 2007, 13 January 0 Noto earthquake 2007, 25 March 1 Chuetsu Offshore earthquake 2007, 16 July 11 Iwate-Miyagi Nairiku earthquake 2008, 14 June 12 Izu Islands earthquake 2009, 9 August 0 Shizuoka earthquake 2009, 11 August 1 Ryukyu Islands earthquake 2010, 26 February 1 Bonin Islands earthquake 2010, 21 December 0 Tohoku earthquake 2011, 11 March 19,759 Miyagi earthquake aftershock 2011, 7 April 4 Fukushima earthquake 2011, 11 April 6 Fukushima earthquake aftershock 2011, 10 July 0 Izu Islands earthquake 2012, 1 January 0 Kamaishi earthquake 2012, 7 December 3 Chiba earthquake 2012, 14 March 3 Noto earthquake 2024, 1 January 360

Mudslides

A mudslide, or mudflow, occurs when rocks, sand, and earth are loosened and fall from hills and mountains due to earthquake, rain or snow. In Japan, over two-thirds of the land is mountainous and therefore prone to mudslides.

Major mudslide events Japan has experienced several major mudslide events, often due to other natural disasters.

Mount Ontake 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. 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. After the disaster, barriers against mudslide were erected in nine locations at the foot of Mt. Ontake.

Wakayama and Nara 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. "Shinsohokai" means that not only soil collapses, but also bedrock. In this case, houses were covered with earth and sand from the mudslide and there were many injured and killed.

Hiroshima In June 2010, Hiroshima experienced heavy rains which caused severe damage, including mudslides and river floods; Shōbara had 64 mm rain in an hour and Hiroshima had 30–50 mm on June 12, 20-40mm on the 13th and 20-50mm on the 14th. Five people were killed and six injured; 1,787 houses were destroyed.

Floods Floods and tsunamis are imbedded in Japanese culture and history. Southern parts of some regions are under sea level like Kyushu, Shikoku and Okinawa. Rising oceans are also making the Tokyo metropolitan area, home to 38 million people, vulnerable to storm surges. Years of pumping up groundwater have caused some parts of the city to sink nearly 5 meters over the past century. This means that large parts of Tokyo are now below sea level and are only protected by outdated dikes.

With a population of 127 million, the population density is very high. Most residential and industrial areas are located in low-lying areas, along rivers; these areas are very vulnerable to river flooding and flash floods. According to a 1985 study, 49 percent of the population and 75 percent of businesses are located in flood-prone areas. 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. These kinds of situations are then called a storm surge. In addition, precipitation is an increasing cause of flooding in Japan.

Flood management Flood management has been important in Japan for generations. 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. Here a narrow path runs along the old river near the inhabited areas. Today there is a monument. Japan has many large-scale projects to protect its inhabitants from the water. For example, there is a lot of emphasis on breaking high waves and a lot of research is being done into the behavior of tsunamis. After the devastating tsunami of 2011, the Japanese government decided to protect all vulnerable villages and towns along the coast by building sea walls that range from 8.5 meters to 24 meters in height. As much as eleven billion is spent on building this 400-kilometer-long concrete wall. Inland, flood management in Japan is also important against river flooding. Many of these projects are also recognizable to us. The government is working on widening the river channels and building dikes. This is to limit the rise in a river's water level by increasing its cross-section and to prevent the land from flooding in times of flooding.

Management of floods include drainage basins, which are used to temporarily store the overflow of the river during a flood and to drain it again after the risk of flooding has passed. This prevents the downstream water levels from rising. In addition, they also include pumping stations; pumps are used to drain rainwater into the river in areas where the water level in the river is higher than the land. Lastly, dredging is also used. This is done to lower the water level in a river by deepening or dredging the river bed. Another important way of flood management is to create so-called shortcuts or shortcuts. The length of a river channel is shortened by straightening bends, so that flood water can flow through it quickly. And a flood management approach widely used by Japan is dams, such as the 186-meter high Kurobe Dam in Toyama Prefecture. These dams are huge, so it often takes years to build them. The function of these dams is to regulate the water flow upstream at the time of a flood, so that the flow is reduced downstream.

Heatwaves Heatwaves have become increasingly common in Japan. June 2022 has seen the worst heatwave in 150 years.

See also List of disasters in Japan by death toll

References

External links Recent natural disasters in Japan-日本では最近の自然災害