Nankai Trough
Japan · subduction interface · 977.8 km of mapped active fault in 21 traces
background as of 7 November 2026.
consistent with baseline
| Window | the last 30.0 days |
|---|---|
| Earthquakes counted | 0 at M4.5 or above |
| Expected in that window | 0.33 |
What this system normally does
From 1995 to 2025 the catalogue holds 122 earthquakes of M4.5 or larger attributable to this system: about 4.07 a year. That figure is what "elevated" on this page is measured against.
The fault itself
| Mapped length | 977.8 km |
|---|---|
| Traces | 21 |
| Tectonic setting | subduction interface |
| Slip types | Subduction_Thrust |
| Depth attributed to it | down to 700.0 km |
| Extent | 29.82 to 35.03 latitude, 132.07 to 140.87 longitude |
Recorded history
NOAA's hazard records hold 28 significant earthquakes and 23 tsunamis attributed to this system since 684.
The deadliest was the 1 September 1923 magnitude 7.9 earthquake (Japan: Tokyo, Yokohama), which killed 105,385 people.
The strongest earthquake on record here was magnitude 8.6, on 26 August 887 (Japan: Nankaido).
The most recent entry is the 10 August 2009 magnitude 6.4 earthquake (Japan: Honshu: S Coast), which killed one person.
Across the entries that record a death toll, 131,551 people died.
| Date | What | Where | Toll |
|---|---|---|---|
| 1 September 1923 | magnitude 7.9 earthquake | Japan: Tokyo, Yokohama | 105,385 dead, 695,000 homes destroyed, $600 million damage |
| 1 September 1923 | tsunami (waves to 13 m) | Sagami Bay | 105,385 dead, 695,000 homes destroyed, $600 million damage |
| 30 December 1703 | magnitude 8.2 earthquake | Japan: off Sw Boso Peninsula | 5,233 dead, 20,162 homes destroyed, damage over $25 million |
| 30 December 1703 | tsunami (waves to 11.7 m) | off Sw Boso Peninsula | 5,233 dead, 20,162 homes destroyed, damage over $25 million |
| 20 September 1498 | magnitude 8.3 earthquake | Japan: Enshunada Sea | 5,000 dead, 1,000 homes destroyed, damage $5 to 25 million |
| 3 February 1605 | magnitude 7.9 earthquake | Japan: Nankaido | 5,000 dead, 400 homes destroyed, damage $5 to 25 million |
| 3 February 1605 | tsunami (waves to 10 m) | Nankaido | 5,000 dead, 700 homes destroyed, damage $5 to 25 million |
| 20 September 1498 | tsunami (waves to 10 m) | Enshunada Sea | 5,000 dead, 1,000 homes destroyed, damage $5 to 25 million |
| 24 December 1854 | tsunami (waves to 28 m) | Nankaido | 3,000 dead, 20,000 homes destroyed, damage over $25 million |
| 24 December 1854 | magnitude 8.4 earthquake | Japan: Nankaido | 3,000 dead, 20,000 homes destroyed, damage over $25 million |
| 28 October 1707 | magnitude 8.4 earthquake | Japan: Enshunada | 2,000 dead, 10,000 homes destroyed, damage $5 to 25 million |
| 28 October 1707 | tsunami (waves to 11 m) | Enshunada | 2,000 dead, 10,000 homes destroyed, damage over $25 million |
| 20 December 1946 | magnitude 8.3 earthquake | Japan: Honshu: S Coast | 1,362 dead, 11,661 homes destroyed, damage over $25 million |
| 20 December 1946 | tsunami (waves to 6.6 m) | Honshu: S Coast | 1,362 dead, 11,661 homes destroyed, damage over $25 million |
| 7 December 1944 | magnitude 8.1 earthquake | Japan: off Southeast Coast Kii Peninsula | 1,223 dead, 29,205 homes destroyed, damage $5 to 25 million |
| 7 December 1944 | tsunami (waves to 10 m) | off Southeast Coast Kii Peninsula | 1,223 dead, 29,205 homes destroyed, damage $5 to 25 million |
| 3 February 1605 | magnitude 7.9 earthquake | Japan: Enshunada | 1,001 dead, 80 homes destroyed, damage $5 to 25 million |
| 3 February 1605 | tsunami | Enshunada | 1,001 dead, 80 homes destroyed, damage $5 to 25 million |
| 23 December 1854 | tsunami (waves to 21 m) | Enshunada Sea | 1,000 dead, 8,900 homes destroyed, damage over $25 million |
| 23 December 1854 | magnitude 8.3 earthquake | Japan: Enshunada Sea | 1,000 dead, 8,900 homes destroyed, damage over $25 million |
| 3 August 1361 | magnitude 8.4 earthquake | Japan: Nankaido | 660 dead, 1,700 homes destroyed, damage over $25 million |
| 3 August 1361 | tsunami | Nankaido | 660 dead, 1,700 homes destroyed, damage over $25 million |
| 17 December 1096 | magnitude 8.4 earthquake | Japan: Enshunada | 400 dead |
| 25 November 1930 | magnitude 7.1 earthquake | Japan: Honshu: Idu | 259 dead, 8,099 homes destroyed, damage over $25 million |
| 8 May 1974 | tsunami (waves to 0.2 m) | Tokaido | 30 dead, 134 homes destroyed, damage $1 to 5 million |
These are the 25 deadliest and largest of 51 entries. A dash means NOAA recorded no number, not that nobody died. Older entries are fewer because fewer were written down, not because less happened.
Recorded history: NOAA NCEI hazard databases, public domain, retrieved 2026-10-22.
Published rupture probability
Cabinet Office of Japan, from the Earthquake Research Committee publishes a probability for this system. It is their figure, not ours:
| Probability | 70 to 80% |
|---|---|
| For an earthquake of | M8.0 or larger |
| Within | 30 years |
| As of | 2013 |
For an M8-class Nankai Trough earthquake. Japan revises this figure periodically.
Read the issuer's own publication
Who to listen to if you live here
Japan Meteorological Agency is the agency that tells people on this system what to do. https://www.jma.go.jp/jma/en/Activities/earthquake.html (in English)
Other systems in Japan
Where these numbers come from
Fault geometry, length and segment counts: GEM Global Active Faults Database (GEM GAF-DB), GEM Foundation, https://github.com/GEMScienceTools/gem-global-active-faults Licence: CC-BY-SA-4.0. Figures derived from it here are offered under the same licence. Earthquake counts, magnitudes and depths: United States Geological Survey, public domain. The activity judgement is ours, computed from those two inputs, and is not a statement by either agency.