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J-SHIS EARTHQUAKE SOURCE MODEL

Mega earthquakes along the Kuril Trench

千島海溝沿いの超巨大地震

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

Reference model · not a forecast
Modelled magnitudeMw 8.7–9.2

The range of earthquake sizes represented by the whole model.

Chance within 30 years37%

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

Chance within 50 years56%

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

This model in plain language

This is a model of a broad plate boundary where one plate descends beneath another. Different sections may rupture in different combinations. The model covers an overall magnitude of Mw 8.7–9.2. Its source elements span depths of 0–61.68 km below the surface. It considers 13 rupture patterns; this is not the number of expected earthquakes. Its 30-year long-term probability is 37%, 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 depthShallow0 kmMid-range30.8 kmDeep61.7 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 8.7–9.2

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 years37%Within 50 years56%

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. Kushiro, Kushiro City
  2. Obihiro City
  3. Tomakomai City
  4. Noboribetsu City
  5. Namporo Town
  6. Yuni Town
  7. Naganuma Town
  8. Kuriyama Town
  9. Minamifurano Town
  10. Shiraoi Town
  11. Atsuma Town
  12. Mukawa Town
Show 48 more places
  1. Hidaka, Hidaka Town
  2. Biratori Town
  3. Niikappu Town
  4. Urakawa Town
  5. Samani Town
  6. Erimo Town
  7. Shinhidaka Town
  8. Otofuke Town
  9. Shimizu Town
  10. Memuro Town
  11. Nakasatsunai Village
  12. Sarabetsu Village
  13. Taiki Town
  14. Hiroo Town
  15. Makubetsu Town
  16. Ikeda Town
  17. Toyokoro Town
  18. Urahoro Town
  19. Shibecha Town
  20. Teshikaga Town
  21. Tsurui Village
  22. Shiranuka Town
  23. Betsukai Town
  24. Nakashibetsu Town
  25. Shibetsu Town
  26. Nemuro City
  27. Shari Town
  28. Koshimizu Town
  29. Abira Town
  30. Shihoro Town
  31. Shikaoi Town
  32. Hombetsu Town
  33. Kushiro Town
  34. Akkeshi Town
  35. Hamanaka Town
  36. Mutsu City
  37. Higashidori Village
  38. Hakodate City
  39. Abashiri City
  40. Chitose City
  41. Furano City
  42. Eniwa City
  43. Kitahiroshima City
  44. Nakafurano Town
  45. Bihoro Town
  46. Kiyosato Town
  47. Ozora Town
  48. Ashoro 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
ACHSM
The identifier used for this model inside J-SHIS.
Estimation method code
XXX
An abbreviation for the statistical process used to calculate probability. It is not a danger grade.
Source elements
44,217
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
0–61.68 km
The modelled depth range below the ground surface.
Rupture patterns
13
Alternative rupture arrangements or sequences considered by the model.
Display grid cells
1,681
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 →