Japan has a long history of natural disasters. BOSAI explores how to overcome them and save lives with the power of science. This first program is about tsunami. First, we visit ruins in Miyagi Prefecture from the 2011 Great East Japan Earthquake, and learn how the psychological state of "normalcy bias" affects humans in a disaster. We also look at the characteristics of a tsunami, and new initiatives created with the aid of a supercomputer to help with evacuation drills and other countermeasures.

Japan's cities are often located in low-lying areas along rivers and are paved with concrete and asphalt, putting them at risk of flooding in the event of heavy rain. In recent years, significant damage has been caused by overflowing drains and backflow along drainage channels. In this program, we'll look at the unique mechanisms of urban flooding and explore ways to protect against disaster.

Typhoon Jebi, which struck Osaka Prefecture in 2018, is said to be the first typhoon to have hit a modern metropolis in Japan, and many buildings were damaged. According to experts, the destruction of those buildings could not be explained by the maximum instantaneous wind speed observed by the Japan Meteorological Agency. Urban structures may be to blame. Researchers believe that eddies of wind intensify around high buildings, causing sudden gusts of strong winds that exceed the observed values. In this episode, we will scientifically analyze the mechanism of sudden urban windstorms and explore ways to save lives.

In the 2011 Great East Japan Earthquake, high-rise buildings in Tokyo's Shinjuku district, some 400 kilometers away from the epicenter, continued to sway significantly for 13 minutes. This is thought to have occurred when the high-rise buildings experienced resonance from the earthquake's "long-period seismic motion." Furthermore, in the 2016 Kumamoto earthquakes, a type of motion called a "long-period pulse" was recorded for the first time in Japan, presenting a new challenge for earthquake countermeasures. In addition to examining these types of earthquake motion, we'll also look at the effects of earthquakes on buildings and explore ways to save lives.

Localized torrential rain is occurring with greater frequency in Japan. Flash floods from the heavy rain not only cause rivers to overflow but threaten homes and human life. This kind of weather has been difficult to predict, given the short timeframe between the formation of cumulonimbus clouds and the onset of rain. Yet a new type of radar called "phased-array radar" and a simulation using a Japanese supercomputer have been developed to forecast local downpours 10 minutes in advance. In this episode, we'll take a closer look at how the latest technology is being used to forecast localized torrential rain and protect lives.

An increase in heavy rainfall in recent years has made debris flows a frequent problem in Japan. We'll look at research underway to help with their early detection and explore ways to protect lives.In recent years, debris flows have become more frequent in Japan due to an increase in heavy rainfall. Given that about 70% of Japan's land area is covered by mountains and forests, they have become a significant issue. After large-scale debris flows struck parts of Hiroshima Prefecture in 2014 and 2018, scientists found that debris flows tend to start out small and then repeatedly recur, causing significant damage. Research is now underway to determine the locations where debris flows are likely to occur based on topographical and geological data, and install sensors that can detect the very first debris flow. Information from these sensors can then help residents evacuate as quickly as possible. In this program, we'll introduce the latest research to save lives from debris flows.

Mt. Fuji has been an object of faith for many Japanese. On the other hand, it has also caused numerous disasters with repeated eruptions. According to a simulation released by the Japanese government in March 2021, the next eruption could cause up to 10cm of volcanic ash to accumulate in Tokyo, about 100km away, within a few hours. Volcanic ash contains small jagged pieces of volcanic glass that can cause severe eye pain. Furthermore, volcanic ash can become electrically conductive when it absorbs rain, damaging power grids and triggering power outages. Moreover, it is expected to cripple the transport system, including automobiles, trains and airplanes, leading to significant damage in the urban areas. What can we do to prepare for the eruption of Mt. Fuji? Find out the things you can do in your daily life to protect yourself from volcanic disasters.

In Japan, the temperature is continuing to rise due to the effects of global warming and heatstroke cases are also on the rise. Heatstroke is a condition in which the body loses the ability to regulate its own temperature in a hot humid environment. It causes nausea, dizziness, delirium and could even lead to death. Professor Akimasa Hirata of Nagoya Institute of Technology developed a way to simulate the core body temperature using computer models of the human body. His research is helping to predict the risk of heatstroke. Furthermore, another research is underway that combines this technology with urban climate simulations. Discover ways to protect yourself from heatstroke through the latest research.

The 2018 torrential rains in western Japan killed 51 people in the Kurashiki City town of Mabi in Okayama Prefecture. Many of the victims drowned on the first floor of their home despite having a second story available. Why weren't they able to evacuate? A simulation of the flooding revealed that flood waters rose at a much faster rate than initially expected, highlighting the importance of early evacuation during heavy rain and flooding. Meanwhile, home builders have been developing completely new houses that prevent damage from flooding. In this program, we'll take a closer look at the threat of home flooding as well as some of the latest countermeasures.

Japan experiences an average of 23 tornadoes per year. They often cause serious damage when they strike in populated areas such as plains or along the sea. Tornadoes are also considered the most difficult type of weather phenomenon to predict, with few effective countermeasures available. Now, research is underway to capture the process of tornado formation using the latest radar, and to predict tornadoes using data from ground-based observation equipment. We'll take a closer look at the latest developments in tornado research and new efforts underway to protect lives.

Avalanches occur suddenly, damaging houses and injuring people. Many of the avalanches that occurred in Yamanashi Prefecture in 2014 took place in locations where avalanches are uncommon. We now know that many of these were "slab avalanches," in which a slab of surface layer snow is dislodged. How and why did these slab avalanches occur? We'll look at the latest efforts to better understand the underlying mechanisms, and the steps being taken to save lives.

The 1983 eruption of Tokyo's Miyake Island resulted in the burial or loss of approximately 400 houses as well as a school built of reinforced concrete that was also buried by lava flow. The hazard map for Mount Fuji was revised in 2021, revealing the possibility of far greater damage from lava flows. Why have the damage assumptions been increased? And what countermeasures should be taken? In this episode, we'll look at the latest research on lava flows from Mount Fuji.

In September 2018, the Hokkaido Eastern Iburi Earthquake knocked out power of the entire region, affecting up to 2.95 million households. The tremor caused several power plants to shut down, disrupting the electrical frequency. This led to a chain reaction of other power plants to shut down. People's lives were greatly affected, as medical equipment failed and logistics systems were disrupted. What can we do to prevent such large-scale power outages? Find out what power companies and local communities are doing to take steps against massive blackouts.