Situation survey of large-scale embankment sites

In response to the Great Hanshin-Awaji Earthquake of 1995 and the Niigata Chuetsu Earthquake of 2004, the Residential Land Development Regulation Law (hereinafter referred to as the "law") was revised (2006), regardless of land inside and outside the "* 1 Residential Land Development Construction Restricted Area". ※2 A survey was conducted from 2006 to 2009 to confirm the distribution status of large-scale embankment sites.

※1 Residential land development restricted area
It is an area of an urban area or a land that is going to become an urban area where a disaster is likely to occur with residential land development, which was designated to regulate construction related to residential land development.
⇒Ministry of Land, Infrastructure, Transport and Tourism website "Effective status of the Regulation Law for Residential Land Development" (outside site)

Yokohama City has designated about 63% (27,200 hectares), which is about two-thirds of the city area, as a "Restricted Residential Land Development Construction Construction Zone" (approximately 2.7% for the entire national land).

※2 Large-scale embankment site
The survey was conducted with an embankment area of 3,000 square meters or more (valley-filled type) or an angle of the ground surface before embankment to the horizontal plane of 20 degrees or more, and the height of the embankment is 5 meters or more (abdominated type). Was.

Of the city area, approximately 435 square kilometers, approximately 312 square kilometers were extracted as surveyed areas, excluding natural terrain of flatlands and hills, golf courses, forest areas, and landfills.
“Target Area Map” (PDF: 739KB)

As for the status of large-scale embankment sites, as topographic data before the development, topographic data (digital mapping data) from 2002 to 19 are superimposed on old topographic maps and aerial photographs, and large-scale embankment sites are extracted from the altitude difference. (For valley fill type, a series of embankments, including those with a height of 2 meters or more, are extracted from the accuracy of survey data).

（PDF：12,710KB）
※ Click the figure above to see the enlarged figure. (Be careful because the file size is large!)

In addition to superimposing the topographic data, as a result of confirming the embankment site by on-site reconnaissance, there were 3,271 large-scale embankment sites in the city.

The “Status Survey Map of Large-scale Embankment Sites” has an error of around 1 meter in horizontal and vertical directions depending on the accuracy of the topographic data before use. In addition, large-scale embankment sites before the war have errors of about 3 to 5 meters in horizontal and vertical directions.

Status of the development of Yokohama City

1. The construction before the law was enacted in 1962 was relatively small, and is often found in old urban areas (Nishi Ward, Naka Ward, Minami Ward) and along the Tokaido (Tsurumi Ward to Totsuka Ward).
2. Kohoku Ward, Midori Ward, Aoba Ward, Tsuzuki Ward  , and the southern part of the city area (Konan Ward, Kanazawa Ward and Sakae Ward) are often found in the northern part of theslope ground area, such as Kohoku New Town.
3. In recent years, residential land development with large-scale kimorido has been carried out on land outside the "Restricted Land Development Zone" in the western part of the city area (Seya Ward and Izumi Ward).

The “Status Survey Map of Large-Scale Embankment Sites” is designed to help citizens know that large-scale embankment sites are nearby. We will make use of it in "disaster prevention town development" that leads to prevention and reduction of damage.

We made brochure to have citizens know about large-scale embankment sites and to have them confirm their land to live and prepare for earthquakes.

Brochures are distributed at the Citizen Information Center on the 3rd floor of the City Hall, each ward office, Housing and Architecture Bureau Building Disaster Prevention Section and Residential Land Examination Section.

(PDF format) (PDF: 17,261KB)

※ Please note that the file size is large.

You can also check the location and scale of the large-scale embankment site in the city at "Supering hazard map", a site operated by the Ministry of Land, Infrastructure, Transport and Tourism.
On this site, it is possible to superimpose maps, aerial photographs, other disaster risk information, etc. that show the location of large-scale embankment sites and buildings.

※Large-scale embankment sites do not immediately indicate dangerous embankment sites, but just because residential land exists in large-scale embankment sites does not necessarily mean that the residential land is dangerous. .
For this reason, large-scale embankment sites are listed not as disaster risk information but as information on the characteristics and origin of land in the hazard map.

⇒hazard map, Geographical Survey Institute, Ministry of Land, Infrastructure, Transport and Tourism (outside site)

How to display large-scale embankment sites

1. Enter the Address of the location you want to check in the search box at the top of the screen to search.
2. Click "Select all information" in "Select information" on the left side of the screen.
3. In the "Information List", click "Characteristics and Structures of Land"
4. Select and display "Large-scale embankment site"
   

Q & A regarding the status survey of large-scale embankment sites

For large-scale embankment sites, please contact the Housing and Architecture Bureau Residential Land Examination Division Residential Land Planning Section.