Reviewed by USGSRomania50y ago
M7.5 earthquake 2 km N of Spulber, Romania
Friday, March 4, 1977, 19:21:54 UTC · 45.772°N, 26.761°E
A magnitude 7.5 earthquake struck 2 km N of Spulber, Romania on Friday, March 4, 1977, 19:21:54 UTC, at a depth of 94.0 km (intermediate). It is the strongest earthquake within 300 km since an M7.7 on November 10, 1940.
- Magnitude
- 7.5
- Major · mwc
- Depth
- 94 km
- Intermediate
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- VIII
- Severe (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 200 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
2.7 megatons of TNT
That is about 178 times the Hiroshima bomb. It released about 5,623 times the energy of a magnitude 5.0.
Tectonic setting
552 km
from the nearest mapped plate boundary, between the Anatolian and Eurasian plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: intermediate
94 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 200 km
USGS lists 1 M2.5+ earthquake within 200 km in the following 30 days; the largest was M4.9 on March 5, 1977. 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 16 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.713 km ESE of Comandău, RomaniaNovember 10, 1940 · 27 km W of this epicenter
- 6.7RomaniaMarch 29, 1934 · 15 km NW of this epicenter
- 6.77 km WNW of Nereju Mic, RomaniaSeptember 7, 1945 · 13 km W of this epicenter
- 6.612 km NNW of Gura Teghii, RomaniaOctober 22, 1940 · 36 km SW of this epicenter
- 6.611 km E of Ghelinţa, RomaniaOctober 6, 1908 · 34 km NW of this epicenter
- 6.41 km SE of Bruiu, RomaniaJanuary 26, 1916 · 159 km W of this epicenter
- 6.03 km WNW of Matca, RomaniaMay 25, 1912 · 57 km E of this epicenter
- 5.810 km WNW of Paltin, RomaniaNovember 1, 1929 · 14 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 8 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 2,687 recorded deaths. The most severe:
- 1977M7.5
Bucharest
4 Mar 1977 · 5 km away
1,641 deaths$2.0 billion damage
- 1940M7.3
Romania
10 Nov 1940 · 4 km away · intensity X
1,000 deaths$10 million damage
- 1838M6.9
Carpathian Fold,Vrancea
23 Jan 1838 · 15 km away · intensity VIII
42 deathsModerate damage ($1–5M)tsunami
- 1901M7.2
Balchik
31 Mar 1901 · 298 km away · intensity X
4 deathsSevere damage ($5–24M)tsunami
- 1829
Bucharest
26 Nov 1829 · 182 km away · intensity X
Severe damage ($5–24M)
- 1802M7.4
Carpathian Fold,Vrancea
26 Oct 1802 · 15 km away · intensity X
Moderate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.