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J-SHIS EARTHQUAKE SOURCE MODEL

Itoigawa-Shizuoka-kozosen fault zone (Central southern segment/Southern segment)

糸魚川－静岡構造線断層帯（中南部と南部が同時に活動）

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

Reference model · not a forecast
Modelled magnitudeMw 7.3

The range of earthquake sizes represented by the whole model.

Chance within 30 years0.01%

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

Chance within 50 years0.02%

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 2–19.56 km below the surface. Its 30-year long-term probability is 0.01%, 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-range10.8 kmDeep19.6 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 years0.01%Within 50 years0.02%

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. Minobu Town
  2. Hayakawa Town
  3. Komagane City
  4. Sakuho Town
  5. Tateshina Town
  6. Miyada Village
  7. Nirasaki City
  8. Fuefuki City
  9. Ichikawamisato Town
  10. Narusawa Village
  11. Fujikawaguchiko Town
  12. Kawakami Village
Show 47 more places
  1. Nagawa Town
  2. Oshika Village
  3. Shizuoka Aoi Ward
  4. Shizuoka Suruga Ward
  5. Fujinomiya City
  6. Fuji City
  7. Kawanehoncho Town
  8. Kofu City
  9. Fujikawa Town
  10. Showa Town
  11. Yamanakako Village
  12. Ina, Ina City
  13. Minamiminowa Village
  14. Shizuoka Shimizu Ward
  15. Numazu City
  16. Yamanashi
  17. Fujiyoshida City
  18. Minamialps City
  19. Kai City
  20. Oshino Village
  21. Matsumoto, Matsumoto City
  22. Saku City
  23. Koumi Town
  24. Minamiaiki Village
  25. Kitaaiki Village
  26. Yamagata Village
  27. Tsuru City
  28. Hokuto City
  29. Chuo City
  30. Okaya City
  31. Chino City
  32. Shiojiri, Shiojiri City
  33. Chikuma City
  34. Azumino City
  35. Tatsuno Town
  36. Minowa Town
  37. Asahi Village
  38. Sakaki Town
  39. Omachi City
  40. Tomi City
  41. Fujimi Town
  42. Hara Village
  43. Shizuoka
  44. Ueda City
  45. Nagano
  46. Shimosuwa Town
  47. Suwa 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
F01622C
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
6
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
2–19.56 km
The modelled depth range below the ground surface.
Element length
5.7–24 km
The length of individual source elements, not necessarily the total length of a fault zone.
Element width
14–22 km
The width of the inclined source elements below ground.
Dip angle
45–70 °
The element’s tilt from horizontal: 0° is horizontal and 90° is vertical.
Strike
116–205.1 °
The compass direction in which an element extends, measured clockwise from north.
Display grid cells
20
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 →