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J-SHIS EARTHQUAKE SOURCE MODEL

Itoigawa-Shizuoka-kozosen fault zone (Northern segment/Central northern segment)

糸魚川－静岡構造線断層帯（北部と中北部が同時に活動）

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

Reference model · not a forecast
Modelled magnitudeMw 7.2

The range of earthquake sizes represented by the whole model.

Chance within 30 years3.19%

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

Chance within 50 years5.04%

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 7.2. Its source elements span depths of 2–16.12 km below the surface. Its 30-year long-term probability is 3.19%, 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-range9.1 kmDeep16.1 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 7.2

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 years3.19%Within 50 years5.04%

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. Sakaki Town
  2. Nagano, Nagano City
  3. Matsumoto, Matsumoto City
  4. Suzaka City
  5. Omachi City
  6. Shiojiri, Shiojiri City
  7. Chikuma City
  8. Tateshina Town
  9. Aoki Village
  10. Tatsuno Town
  11. Omi Village
  12. Yamagata Village
Show 40 more places
  1. Asahi Village
  2. Chikuhoku Village
  3. Hakuba Village
  4. Otari Village
  5. Shinano Town
  6. Ogawa Village
  7. Itoigawa City
  8. Myoko City
  9. Nagano
  10. Ueda City
  11. Okaya City
  12. Chino City
  13. Tomi City
  14. Azumino City
  15. Shimosuwa Town
  16. Minowa Town
  17. Ikusaka Village
  18. Matsukawa Village
  19. Obuse Town
  20. Kijimadaira Village
  21. Iizuna Town
  22. Nakano City
  23. Fujimi Town
  24. Hara Village
  25. Minamiminowa Village
  26. Nyuzen Town
  27. Hokuto City
  28. Suwa City
  29. Iiyama City
  30. Nagawa Town
  31. Joetsu City
  32. Kurobe City
  33. Ina, Ina City
  34. Minamiaiki Village
  35. Kitaaiki Village
  36. Saku City
  37. Koumi Town
  38. Toyama
  39. Yamanashi
  40. Niigata

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
F01622A
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
9
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
2–16.12 km
The modelled depth range below the ground surface.
Element length
5.8–33.9 km
The length of individual source elements, not necessarily the total length of a fault zone.
Element width
4–14 km
The width of the inclined source elements below ground.
Dip angle
30–70 °
The element’s tilt from horizontal: 0° is horizontal and 90° is vertical.
Strike
2–343.7 °
The compass direction in which an element extends, measured clockwise from north.
Display grid cells
19
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 →