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J-SHIS EARTHQUAKE SOURCE MODEL

Median Tectonic Line (MTL) fault zone (FROM Sanuki-sanmyaku-nanen western segment TO Ishizuchi-sanmyaku-hokuen western segment)

中央構造線断層帯（讃岐山脈南縁西部区間～石鎚山脈北縁西部区間が同時に活動）

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

Reference model · not a forecast
Modelled magnitudeMw 7.5

The range of earthquake sizes represented by the whole model.

Chance within 30 years0.02%

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

Chance within 50 years0.05%

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 7.5. Its source elements span depths of 2–16 km below the surface. It considers 2 rupture patterns; this is not the number of expected earthquakes. Its 30-year long-term probability is 0.02%, 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-range9 kmDeep16 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 7.5

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 years0.02%Within 50 years0.05%

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. Okayama Kita Ward
  2. Soja City
  3. Ehime
  4. Matsuyama City
  5. Yawatahama City
  6. Iyo City
  7. Toon City
  8. Tobe Town
  9. Imabari City
  10. Saijo City
  11. Ozu City
  12. Seiyo City
Show 48 more places
  1. Kumakogen Town
  2. Uchiko Town
  3. Ikata Town
  4. Geisei Village
  5. Okayama Naka Ward
  6. Yakage Town
  7. Miyoshi City
  8. Mitoyo City
  9. Shikokuchuo City
  10. Ibara City
  11. Setouchi City
  12. Higashihiroshima City
  13. Kanonji City
  14. Niihama City
  15. Okayama
  16. Kurashiki City
  17. Waki Mima Anabuki, Mima City
  18. Handa Sadamitsu, Tsurugi Town
  19. Higashimiyoshi Town
  20. Kagawa
  21. Takamatsu City
  22. Marugame City
  23. Zentsuji City
  24. Sanuki City
  25. Miki Town
  26. Ayagawa Town
  27. Tadotsu Town
  28. Manno Town
  29. Okayama Higashi Ward
  30. Onomichi City
  31. Osakikamijima Town
  32. Yanai City
  33. Suo Oshima Town
  34. Yoshinogawa City
  35. Awa City
  36. Sakaide City
  37. Higashikagawa City
  38. Utazu Town
  39. Kotohira Town
  40. Kamijima Town
  41. Aki City
  42. Nankoku City
  43. Susaki City
  44. Konan City
  45. Motoyama Town
  46. Otoyo Town
  47. Okawa Village
  48. Ino Town

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
F0201FH
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
4
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
2–16 km
The modelled depth range below the ground surface.
Element length
42–86 km
The length of individual source elements, not necessarily the total length of a fault zone.
Element width
12–18 km
The width of the inclined source elements below ground.
Dip angle
40–90 °
The element’s tilt from horizontal: 0° is horizontal and 90° is vertical.
Strike
248.7–255.8 °
The compass direction in which an element extends, measured clockwise from north.
Rupture patterns
2
Alternative rupture arrangements or sequences considered by the model.
Display grid cells
42
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 →