Reviewed by USGSJapan53y ago
M4.0 earthquake 171 km SSE of Tateyama, Japan
Saturday, July 28, 1973, 22:14:13 UTC · 33.480°N, 140.304°E
A magnitude 4.0 earthquake struck 171 km SSE of Tateyama, Japan on Saturday, July 28, 1973, 22:14:13 UTC, at a depth of 89.0 km (intermediate).
- Magnitude
- 4.0
- Light · mb
- Depth
- 89 km
- Intermediate
- 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
45 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: intermediate
89 km
Intermediate-depth earthquakes usually break inside a plate that is sinking into the mantle. Shaking spreads over a wide area but is gentler at the epicenter than a shallow quake of the same size.
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 1 M2.5+ earthquake within 50 km in the following 30 days; the largest was M4.6 on August 6, 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 242 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 · 218 km NW of this epicenter
- 7.9174 km SE of Katsuura, JapanNovember 25, 1953 · 135 km NE of this epicenter
- 7.85 km E of Tateyama, JapanSeptember 2, 1923 · 171 km N of this epicenter
- 7.450 km SSW of Ōyama, JapanJanuary 21, 1906 · 224 km W of this epicenter
- 7.3206 km SSE of Wada, JapanDecember 4, 1972 · 54 km E of this epicenter
- 7.3190 km SE of Hasaki, JapanSeptember 7, 1906 · 249 km NE of this epicenter
- 7.264 km ENE of Hasaki, JapanJune 1, 1923 · 294 km N of this epicenter
- 7.2176 km SE of Shingū, JapanFebruary 12, 1910 · 268 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 29 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 120,765 recorded deaths. The most severe:
- 1923M7.9
Tokyo, Yokohama
1 Sep 1923 · 195 km away
105,385 deaths$600 million damagetsunami
- 1855M7.0
Tokyo
11 Nov 1855 · 246 km away
6,757 deathsExtreme damage ($25M+)tsunami
- 1703M8.2
Off Sw Boso Peninsula
30 Dec 1703 · 171 km away
5,233 deathsExtreme damage ($25M+)tsunami
- 1707M8.4
Enshunada
28 Oct 1707 · 241 km away
2,000 deathsSevere damage ($5–24M)tsunami
- 1854M8.3
Enshunada Sea
23 Dec 1854 · 230 km away
1,000 deathsExtreme damage ($25M+)tsunami
- 1930M7.1
Honshu: Idu
25 Nov 1930 · 207 km away
259 deathsExtreme damage ($25M+)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.