Japan earthquakes, down to the local station
EN
Open interactive map
MenuMore
J-SHIS EARTHQUAKE SOURCE MODEL

Iwakuni-Itsukaichi fault zone (Koi fault segment/Iwakuni fault segment)

岩国－五日市断層帯（己斐断層区間と岩国断層区間が同時に活動）

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 years0.19%

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

Chance within 50 years0.31%

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 2–20 km below the surface. Its 30-year long-term probability is 0.19%, 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-range11 kmDeep20 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 years0.19%Within 50 years0.31%

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. Hiroshima
  2. Hiroshima City Asakita Ward
  3. Kure City
  4. Kumano Town
  5. Hiroshima City Higashi Ward
  6. Hiroshima City Aki Ward
  7. Higashihiroshima City
  8. Akitakata City
  9. Akiota Town
  10. Kitahiroshima Town
  11. Hiroshima City Asaminami Ward
  12. Hatsukaichi City
Show 35 more places
  1. Fuchu Town
  2. Hofu City
  3. Kudamatsu City
  4. Hikari City
  5. Shunan City
  6. Kaminoseki Town
  7. Yoshika Town
  8. Hiroshima City Nishi Ward
  9. Hiroshima City Saeki Ward
  10. Otake City
  11. Etajima City
  12. Yamaguchi
  13. Yanai City
  14. Suo Oshima Town
  15. Waki Town
  16. Tabuse Town
  17. Kunisaki City
  18. Tsuwano Town
  19. Hiroshima City Minami Ward
  20. Kaita Town
  21. Saka Town
  22. Iwakuni City
  23. Hirao Town
  24. Himeshima Village
  25. Hiroshima City Naka Ward
  26. Shimane
  27. Bungotakada City
  28. Yamaguchi City
  29. Osakikamijima Town
  30. Ube City
  31. Takehara City
  32. Oita
  33. Mihara City
  34. Matsuyama City
  35. Ehime

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
F01850A
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
2–20 km
The modelled depth range below the ground surface.
Element length
24–48 km
The length of individual source elements, not necessarily the total length of a fault zone.
Element width
18 km
The width of the inclined source elements below ground.
Dip angle
70–90 °
The element’s tilt from horizontal: 0° is horizontal and 90° is vertical.
Strike
219.4–236.3 °
The compass direction in which an element extends, measured clockwise from north.
Display grid cells
15
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 →