Reviewed by USGSBulgaria99y ago
M5.8 earthquake 4 km NW of Simeonovgrad, Bulgaria
Wednesday, April 25, 1928, 09:25:56 UTC · 42.064°N, 25.794°E
A magnitude 5.8 earthquake struck 4 km NW of Simeonovgrad, Bulgaria on Wednesday, April 25, 1928, 09:25:56 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M7.1 on April 18, 1928.
- Magnitude
- 5.8
- Moderate · mw
- Depth
- 15 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 earthquake
In context
How big was it, and why here?
Energy released
9 kilotons of TNT
That is about 1/2 of the Hiroshima bomb. It released about 18 times the energy of a magnitude 5.0.
Tectonic setting
180 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: shallow
15 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 has not published any M2.5+ earthquake within 75 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 25 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.2Aegean SeaNovember 8, 1905 · 240 km SW of this epicenter
- 7.225 km SE of Malkara, TurkeyAugust 9, 1912 · 185 km SE of this epicenter
- 7.19 km S of Stara Zagora, BulgariaApril 14, 1928 · 34 km N of this epicenter
- 7.13 km W of Brezovo, BulgariaApril 18, 1928 · 70 km NW of this epicenter
- 7.07 km SE of Stara Kresna, BulgariaApril 4, 1904 · 213 km W of this epicenter
- 6.86 km W of Stara Kresna, BulgariaApril 4, 1904 · 224 km W of this epicenter
- 6.730 km SW of Kumbağ, TurkeySeptember 13, 1912 · 193 km SE of this epicenter
- 6.75 km NNE of Lyaskovets, BulgariaJune 14, 1913 · 121 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 28 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 4,301 recorded deaths. The most severe:
- 1912M7.2
Marmara Sea
9 Aug 1912 · 185 km away
2,800 deathsExtreme damage ($25M+)tsunami
- 1894M6.7
Turkey
10 Jul 1894 · 292 km away · intensity X
1,349 deathsSevere damage ($5–24M)tsunami
- 1928M6.8
Chirpan
14 Apr 1928 · 43 km away · intensity X
127 deathsExtreme damage ($25M+)
- 1905M7.2
Aegean Sea
8 Nov 1905 · 240 km away · intensity X
11 deathsModerate damage ($1–5M)tsunami
- 1902M6.5
Thessaloniki
5 Jul 1902 · 268 km away · intensity IX
5 deathsModerate damage ($1–5M)tsunami
- 1901M7.2
Balchik
31 Mar 1901 · 266 km away · intensity X
4 deathsSevere damage ($5–24M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.