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.

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.

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.

The Great East Japan Earthquake and the massive tsunami that followed caused unprecedented damage along the coast of the Tohoku region with waves over 16 meters high. Why was the initial tsunami warning inaccurate? Errors are thought to have occurred as a result of tremors that exceeded what scientists had anticipated. Professor Shunichi Koshimura of Tohoku University is developing a completely new tsunami prediction system after realizing the limits of the current system. The key is to make predictions based on data gathered by observing real-time movements of the earth's crust. This new system is to be applied to the mega earthquake projected to hit Japan in the near future. Find out the latest in tsunami prediction technology that will lead to saving human lives.

In February 2022, an American space exploration company simultaneously launched 49 satellites. Yet not long after, 40 of those satellites fell out of orbit and burned up upon re-entry into the Earth's atmosphere. Similar accidents have occurred frequently in the past. The cause of such incidents is believed to be solar flares, huge explosions that occur on the sun's surface. Solar flares can also lead to other disasters that threaten our daily lives, such as major power outages, radio interference, and communication problems for airplanes and ships. Why do solar flares occur? We'll visit some researchers in Japan that are working hard to understand their mechanism and predict future occurrences.