This year marks ten years since a devastating earthquake and tsunami struck Japan in March 2011. For many Japanese, every March offers a chance to look back on the earthquake and think about disaster prevention.

Due to its geographic location, Japan has been the scene of many natural disasters such as earthquakes and typhoons. Various efforts to make the most of this experience have been made, including construction of levees and embankments, creation of hazard maps and so on. In addition to physical infrastructure to guard against such disasters, folklore has been passed on from generation to generation regarding natural disasters in each locality in an attempt to convey information about what happened and what people learned.

Messages handed down regarding natural disasters

Efforts have been made to use monuments to convey messages about disasters. These are the "Natural Disaster Monuments." Past generations have left monuments trying to convey to future generations what they had experienced and the state of damage from disasters they had witnessed. Among the older ones in Japan, there is the Empo Tsunami Memorial statue, erected in 1694 (seventh year of the Genroku Era) in the town of Ichinomiya, Chiba Prefecture. It was built 17 years after a tsunami caused serious damage in 1677 (Empo 4), for the repose of the souls of about 150 people who had lost their lives. In Kazo City, Saitama Prefecture, the Kampo Second Year Flood Memorial stone was erected in 1774 (Anei 3). In 1742 (Kampo 2), a nearly 90-meter section of a levee collapsed during heavy, prolonged rains, letting waters from the Tone and other rivers burst through to inhabited areas. The monument was built for the repose of the souls of the many who perished in the floods. Many such monuments can still be found in all parts of Japan.

Oral folklore also exists regarding natural disasters. The Sanriku district of Japan's northerly Tohoku region has an expression, "tsunami tendenko." What this means is that if a tsunami is coming, you should rush to higher ground, and save your own life first. This part of Japan has suffered from tsunamis repeatedly since ancient times, and this expression embodies the desire to reduce the number of tsunami victims, even by one.

Folklore from past disasters is key to future protection

Despite the effort that went into creating these monuments and folklore about natural disasters, their valuable messages have in some cases been forgotten by the people living in those areas. Reasons include the passage of time and greater mobility of modern society.

Torrential rains in July 2018 in western Japan caused enormous damage, with 18 people dead or missing and more than 1,250 houses completely or partially destroyed in the town of Saka, Hiroshima Prefecture. In fact, there is a stone marker in that area about a great flood there in 1907 (Meiji 40), but the message had not been adequately conveyed to the people living there today.

How can natural disaster monuments and legends be utilized?

Spurred by the enormous damage in Saka, the Geospatial Information Authority of Japan (GSI) created map symbols in 2019 to indicate the locations of natural disaster monuments. In the same year, it began gathering information from municipalities and posting it on the GSI website. By clicking icons on the website's maps, one can read details about the topography and monuments and get an idea of the kind of disasters that occurred.
https://www.gsi.go.jp/bousaichiri/denshouhi.html

As of March 3, 2021 the website had data on 861 monuments. There are apparently several thousand natural disaster monuments in Japan, however, so many are still missing from the website. One reason for this is that many of the monuments were built long ago, so it takes time for the municipalities to confirm the data, and also this initiative by the GSI is not yet widely known.

The Ministry of Internal Affairs and Communications Fire and Disaster Management Agency (FDMA) has also compiled information on disaster-related folklore throughout Japan on its website.
https://www.fdma.go.jp/publication/database/database009.html
The lore posted includes items that lack scholarly backing. However, by having people know about the kinds of folklore that have been handed down locally, they anticipate increased community awareness and the use of these legends as a tool for disaster prevention education.

Levees and embankments built after a major disaster may leave people feeling reassured that a disaster will probably not occur again. However, there have been cases of levees breaking when conditions exceed design expectations and many instances of people lulled by a sense of security because an embankment was there, who failed to evacuate and were harmed. Even if levees and embankments protect against damage from normal heavy rains, they might not be able to prevent the kinds of large-scale disasters that occur only once in a century.

Together with "hard" physical infrastructure to prevent or reduce the risk of disasters, it is also important to use "soft" measures such as creating hazard maps, using natural disaster monuments, verifying folklore, and conducting disaster drills. Greater resilience is achieved by utilizing multiple means of protection, not relying on just one.

There are real examples where reliance on folklore saved lives. The Aneyoshi district of Miyako City, Iwate was hit by large tsunamis in 1896 (Meiji 29) and 1933 (Showa 8), when most residents became victims. Monuments commemorating those tragedies stand in Aneyoshi, inscribed with the words, "Don't built houses below this point." The residents followed that advice, not building houses in low-lying areas close to sea level, and because of that, not even one residence there was damaged in the disaster of 2011.

New natural disaster monuments being built since the Tohoku earthquake and tsunami disaster of 2011

Since the disaster of 2011, new monuments have been built to warn future generations. Sixty of them, mostly in Japan's Tohoku region, are described on the GSI website. One is at the Isuzu Shrine in the town of Minamisanriku in Motoyoshi District, Miyagi Prefecture. A memorial has been built to mark the point reached by the tsunami, inscribed with the words, "To people in the future, when earthquakes occur, run for ground higher than this." Likewise, in Asahi City, Chiba Prefecture, a new marker shows how high the tsunami reached. A monument adjacent to it describes the damage that was caused by the tsunami.

As we make a point of utilizing the lessons handed down to us from our ancestors, we must also convey what we have learned from our own experiences to our own descendants. Linking of our lives-that is the sentiment contained in the messages conveyed by the natural disaster monuments.

Source: Geospatial Information Authority of Japan website:
https://www.gsi.go.jp/bousaichiri/denshouhi.html