On the 7th of December, to mark the publication of the latest issue of Enjoyable Philosophy, the editorial team held a “Disaster Prevention Philosophy Café” (DPCC) at MoonLight Book Store in Nishi-Chiba. As a guest, we invited Mr. Koji Tachibana who is a professional working on science communication and has organized more than 30 science cafes throughout Japan. In total, 9 people who were mainly from the local neighbourhood participated in the cafe.
The DPPC was a normal philosophy café event but also involved us making a hazard map. The procedure in the first half of making a hazard map is this: we mark on a transparent sheet covering the map the high-risk places for landslides, floods, liquefaction, fires at petrochemical complexes, and the shelters for these disasters, and we also trace along the coast on the modern map covered with a transparent sheet. Then we check the difference between the old and new geography by placing the transparent sheet on the old map published in the Taisho Era (1912-1926; the reign of the Emperor Yoshihito). This method has been developed by Ms. Hikari Suzuki, who works as a mapping instructor certified by the Fire and Disaster Management Agency in Japan. We saw this method reported by a newspaper, and decided to connect it with our philosophy cafe in the neighborhood where the editorial team is located.
On the day of the DPPC, Mr. Tachibana reported some case studies of liquefactions and fires caused by past earthquakes in Chiba-prefecture, and then we all circled the recent Chiba-city map covered by a transparent sheet.
In the geography of Chiba-city, where the landfill is spread along Tokyo Bay, most of the area is at high risk of liquefaction from an earthquake. The participants gathered were from a wide range of age groups, from people in their 20’s to some in their 80’s. They split up and put a round seal on each station on the Sobu-line and the Keiyo-line, and then they traced along the coast with a pen, and drew in the rivers. By checking the hazard maps released by the administration office of Chiba-city and also the participants’ past memories, we drew in the shelters, the high-risk areas for landslides, the areas where iquefactions happened in the past, and the petrochemical complexes.
Finally, we decided to switch the recent map with the old map published in 1922. While all participants were watching silently, the map was switched, and as this happened cheers broke out among them. This was because the area of the city marked as a high-risk landslide area exactly fitted along the coastline of the 1922 map. Also the places where iquefactions happened in the past used to be rice fields, and the most high-risk places for iquefactions after earthquakes used to be all sea! All participants were saying “This all make sense!”. They arrived at the same answer for “Why are certain places at risk of liquefaction and landslide?” by matching the places where actual disasters had happened and the places where some kinds of disasters are expected to happen in the future, with the old geography.
There is one question which had been left unanswered in the end, which was why three stations on the Keiyo-line were build on the mouths of three different rivers. The locations of the three stations and the mouths of the three different rivers in 1922 overlapped, so we thought there might have been some special intention behind this, but no one could guess why they built the stations at these locations which seemed very risky. This question was left as our homework.
To be continued next article.