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J-SHIS EARTHQUAKE SOURCE MODEL

Nishiyama fault zone (Oshima-Oki segment/Nishiyama segment)

西山断層帯（大島沖区間と西山区間が同時に活動）

What this earthquake source model represents and how to read its data.

Reference model · not a forecast
Modelled magnitudeMw 7.3

The range of earthquake sizes represented by the whole model.

Chance within 30 years0.54%

The long-term chance that an earthquake represented by this model occurs within that period.

Chance within 50 years0.89%

The long-term chance that an earthquake represented by this model occurs within that period.

This model in plain language

J-SHIS classifies this as a major active-fault model. It represents the underground area that may rupture along the fault, not one predicted earthquake. The model covers an overall magnitude of Mw 7.3. Its source elements span depths of 2–18 km below the surface. Its 30-year long-term probability is 0.54%, not a prediction of a date.

Japan terrain and the source model in 3D

Use the terrain map and city labels to locate the approximate source area, then switch below ground to inspect its generalised extent and depth. It does not reproduce the original source elements or show future epicentres or rupture progression.

Ctrl-drag to tilt · city names remain visible on the map

Colour shows generalised depthShallow2 kmMid-range10 kmDeep18 km

The 3D terrain gives geographic and city context. The coloured surfaces are coarse regular display cells projected from the underground source area—not the original J-SHIS geometry. They do not show future epicentres or shaking intensity.

How to read the model data

Modelled magnitudeMw 7.3

Magnitude describes the overall size of the modelled earthquake, not the Shindo felt in a particular place. The same magnitude can produce different shaking depending on distance, depth and ground conditions. A range shows both model limits.

Occurrence probability
Within 30 years0.54%Within 50 years0.89%

Probabilities are long-term values in the Y2020 model. They do not predict an earthquake on a particular day, in a particular year or at one exact location. Some models do not provide a value.

Places where J-SHIS considers this model

In J-SHIS calculations, this model is among the leading earthquake sources for these places. It does not mean the earthquake will start inside their boundaries or that every place would shake in the same way.

  1. Asakura City
  2. Oki Town
  3. Soeda Town
  4. Fukuoka
  5. Kitakyushu Wakamatsu Ward
  6. Kitakyushu Yahatanishi Ward
  7. Fukuoka Minami Ward
  8. Fukuoka Nishi Ward
  9. Fukuoka Sawara Ward
  10. Iizuka City
  11. Okawa City
  12. Yukuhashi City
Show 48 more places
  1. Nakama City
  2. Ogori City
  3. Chikushino City
  4. Kasuga City
  5. Onojo City
  6. Munakata City
  7. Dazaifu City
  8. Koga City
  9. Fukutsu City
  10. Ukiha City
  11. Miyawaka City
  12. Kama City
  13. Hisayama Town
  14. Mizumaki Town
  15. Okagaki Town
  16. Keisen Town
  17. Chikuzen Town
  18. Tachiarai Town
  19. Kawara Town
  20. Oto Town
  21. Aka Village
  22. Fukuchi Town
  23. Kitakyushu Kokurakita Ward
  24. Kitakyushu Kokuraminami Ward
  25. Fukuoka Higashi Ward
  26. Fukuoka Hakata Ward
  27. Fukuoka Chuo Ward
  28. Nogata City
  29. Tagawa City
  30. Nakagawa City
  31. Umi Town
  32. Sasaguri Town
  33. Shime Town
  34. Sue Town
  35. Shingu Town
  36. Kasuya Town
  37. Kotake Town
  38. Kurate Town
  39. Itoda Town
  40. Kanda Town
  41. Miyako Town
  42. Kanzaki City
  43. Kiyama Town
  44. Kitakyushu Tobata Ward
  45. Kitakyushu Yahatahigashi Ward
  46. Fukuoka Jonan Ward
  47. Yanagawa City
  48. Chikugo City

Technical model data

J-SHIS identifiers and calculation parameters. You do not need them for an everyday reading of this page.

Model version
Y2020
The edition of J-SHIS data used on this page.
Probability case
MAX
MAX is the J-SHIS calculation case used on this page. It does not mean a certain ‘worst case’ event.
J-SHIS code
F01220B
The identifier used for this model inside J-SHIS.
Estimation method code
SIM
An abbreviation for the statistical process used to calculate probability. It is not a danger grade.
Source elements
2
Source elements are the pieces J-SHIS uses to build the source shape. A larger count means a more detailed or complex model; it is not a hazard score, a fault count or the number of expected earthquakes.
Depth
2–18 km
The modelled depth range below the ground surface.
Element length
42–48 km
The length of individual source elements, not necessarily the total length of a fault zone.
Element width
16 km
The width of the inclined source elements below ground.
Dip angle
90 °
The element’s tilt from horizontal: 0° is horizontal and 90° is vertical.
Strike
142–144.8 °
The compass direction in which an element extends, measured clockwise from north.
Display grid cells
13
Regular aggregated grid cells used to depict the source area. This is not the number of source records or original shapes.

Source and limitations

Source: J-SHIS, operated by Japan’s National Research Institute for Earth Science and Disaster Resilience (NIED). JISHINDESU organises the Y2020 maximum-case data for presentation. This page is not an earthquake prediction, building-safety assessment or evacuation notice. Use current JMA and local-authority information for safety decisions.

In accordance with the J-SHIS terms, we publish only model-level summaries and coarse display geometry that cannot reproduce the original vertex sequences. This is not a redistributed copy of the source dataset.

Data retrieved: 05/09/2026

Open the source data in J-SHIS ↗J-SHIS terms of use ↗Explore local earthquake history →