Reviewed by USGSJapan53y ago
M5.0 earthquake 92 km S of Nemuro, Japan
Friday, August 3, 1973, 06:26:25 UTC · 42.502°N, 145.745°E
A magnitude 5.0 earthquake struck 92 km S of Nemuro, Japan on Friday, August 3, 1973, 06:26:25 UTC, at a depth of 45.0 km (shallow). It is the strongest earthquake within 300 km since an M5.4 on July 29, 1973.
- Magnitude
- 5.0
- Moderate · mb
- Depth
- 45 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: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
477 tons of TNT
That is about 1/32 of the Hiroshima bomb. Each whole step in magnitude is about 32 times more energy.
Tectonic setting
60 km
from the nearest mapped plate boundary, between the Okhotsk and Pacific plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
45 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 75 km
USGS lists 2 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M4.9 on August 4, 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 494 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.21969 Hokkaido Toho-oki EarthquakeAugust 11, 1969 · 198 km NE of this epicenter
- 8.21968 Tokachi-Oki EarthquakeMay 16, 1968 · 267 km SW of this epicenter
- 8.11952 Tokachi-Oki EarthquakeMarch 4, 1952 · 159 km W of this epicenter
- 7.970 km S of Honchō, JapanMay 16, 1968 · 263 km SW of this epicenter
- 7.7277 km SSE of Kushiro, JapanMay 3, 1919 · 206 km S of this epicenter
- 7.719 km ESE of Nemuro, JapanJune 17, 1973 · 81 km N of this epicenter
- 7.542 km SSW of Shikotan, RussiaSeptember 11, 1935 · 125 km NE of this epicenter
- 7.426 km S of Shikotan, RussiaJanuary 29, 1968 · 141 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 34 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 185 recorded deaths. The most severe:
- 1968M8.2
Off East Coast Of Honshu Island
16 May 1968 · 284 km away · intensity VI
52 deaths$131 million damagetsunami
- 1843M8.4
Hokkaido: Yezo, Kushiro, Nemuro
25 Apr 1843 · 60 km away
45 deathsModerate damage ($1–5M)tsunami
- 1952M8.1
Hokkaido
4 Mar 1952 · 161 km away · intensity IX
33 deathsSevere damage ($5–24M)tsunami
- 1973M7.7
Hokkaido Island
17 Jun 1973 · 78 km away · intensity VIII
27 deaths$5 million damagetsunami
- 1856M8.0
Oshima
23 Aug 1856 · 291 km away · intensity V
26 deathsModerate damage ($1–5M)tsunami
- 1894M7.9
Off Coast Of Honshu
22 Mar 1894 · 21 km away · intensity IX
1 deathModerate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.