Reviewed by USGSBulgaria99y ago
M5.1 earthquake 14 km N of Chirpan, Bulgaria
Thursday, April 19, 1928, 01:09:58 UTC · 42.332°N, 25.314°E
A magnitude 5.1 earthquake struck 14 km N of Chirpan, Bulgaria on Thursday, April 19, 1928, 01:09:58 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M5.8 on April 18, 1928.
- Magnitude
- 5.1
- 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 earthquakeDashed circle: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
722 tons of TNT
That is about 1/21 of the Hiroshima bomb. It released about 2 times the energy of a magnitude 5.0.
Tectonic setting
224 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 lists 3 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.8 on April 25, 1928. 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 27 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.2Aegean SeaNovember 8, 1905 · 256 km S of this epicenter
- 7.225 km SE of Malkara, TurkeyAugust 9, 1912 · 233 km SE of this epicenter
- 7.19 km S of Stara Zagora, BulgariaApril 14, 1928 · 27 km E of this epicenter
- 7.13 km W of Brezovo, BulgariaApril 18, 1928 · 22 km W of this epicenter
- 7.07 km SE of Stara Kresna, BulgariaApril 4, 1904 · 182 km W of this epicenter
- 6.86 km W of Stara Kresna, BulgariaApril 4, 1904 · 191 km W of this epicenter
- 6.730 km SW of Kumbağ, TurkeySeptember 13, 1912 · 241 km SE of this epicenter
- 6.75 km NNE of Lyaskovets, BulgariaJune 14, 1913 · 98 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 25 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 2,952 recorded deaths. The most severe:
- 1912M7.2
Marmara Sea
9 Aug 1912 · 233 km away
2,800 deathsExtreme damage ($25M+)tsunami
- 1928M6.8
Chirpan
14 Apr 1928 · 15 km away · intensity X
127 deathsExtreme damage ($25M+)
- 1905M7.2
Aegean Sea
8 Nov 1905 · 256 km away · intensity X
11 deathsModerate damage ($1–5M)tsunami
- 1902M6.5
Thessaloniki
5 Jul 1902 · 253 km away · intensity IX
5 deathsModerate damage ($1–5M)tsunami
- 1901M7.2
Balchik
31 Mar 1901 · 286 km away · intensity X
4 deathsSevere damage ($5–24M)tsunami
- 1901M6.4
Balchik, Kavarna, Blatnitsa, Limanu
31 Mar 1901 · 300 km away · intensity VIII
4 deathsSevere damage ($5–24M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.