Reviewed by USGSJapan54y ago
M4.0 earthquake 248 km SSE of Tateyama, Japan
Wednesday, April 25, 1973, 07:38:56 UTC · 32.957°N, 141.012°E
A magnitude 4.0 earthquake struck 248 km SSE of Tateyama, Japan on Wednesday, April 25, 1973, 07:38:56 UTC, at a depth of 33.0 km (shallow).
- Magnitude
- 4.0
- Light · mb
- Depth
- 33 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
15 tons of TNT
That is about 1/998 of the Hiroshima bomb. A magnitude 5.0 releases about 32 times more energy.
Tectonic setting
83 km
from the nearest mapped plate boundary, between the North American and African plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
33 km
Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.
Did You Feel It?
Where it was felt
No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.
I felt it — report to USGS ↗USGS PAGER estimate
Who was exposed to shaking
USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.
After the main event
Aftershocks within 50 km
USGS lists 3 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.5 on May 17, 1973. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 222 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.05 km SSE of Ōiso, JapanSeptember 1, 1923 · 300 km NW of this epicenter
- 7.9174 km SE of Katsuura, JapanNovember 25, 1953 · 130 km NE of this epicenter
- 7.85 km E of Tateyama, JapanSeptember 2, 1923 · 247 km NW of this epicenter
- 7.3206 km SSE of Wada, JapanDecember 4, 1972 · 42 km N of this epicenter
- 7.3190 km SE of Hasaki, JapanSeptember 7, 1906 · 244 km NE of this epicenter
- 7.238 km SSW of Shimoda, JapanOctober 24, 1905 · 253 km NW of this epicenter
- 7.2193 km SSE of Wada, JapanFebruary 29, 1972 · 56 km N of this epicenter
- 7.1150 km ESE of Hasaki, JapanMarch 13, 1909 · 286 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 17 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 110,881 recorded deaths. The most severe:
- 1923M7.9
Tokyo, Yokohama
1 Sep 1923 · 276 km away
105,385 deaths$600 million damagetsunami
- 1703M8.2
Off Sw Boso Peninsula
30 Dec 1703 · 246 km away
5,233 deathsExtreme damage ($25M+)tsunami
- 1930M7.1
Honshu: Idu
25 Nov 1930 · 293 km away
259 deathsExtreme damage ($25M+)
- 1936
Nii Jima
27 Dec 1936 · 232 km away
3 deathsLimited damage (under $1M)
- 1953M7.4
Kashima
25 Nov 1953 · 132 km away
1 deathLimited damage (under $1M)tsunami
- 1782M7.3
Tokaido, Japan
22 Aug 1782 · 267 km away
Severe damage ($5–24M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.