Reviewed by USGSItaly118y ago
M5.4 earthquake 5 km WSW of Ambra, Italy
Wednesday, August 25, 1909, 00:22:13 UTC · 43.390°N, 11.541°E
A magnitude 5.4 earthquake struck 5 km WSW of Ambra, Italy on Wednesday, August 25, 1909, 00:22:13 UTC, at a depth of 15.0 km (shallow). No earthquake of this size or larger appears within 300 km in the USGS catalog since 1900.
- Magnitude
- 5.4
- 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
2 kilotons of TNT
That is about 1/8 of the Hiroshima bomb. It released about 4 times the energy of a magnitude 5.0.
Tectonic setting
478 km
from the nearest mapped plate boundary, between the Eurasian and African 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 1 M2.5+ earthquake within 75 km in the following 30 days; the largest was M5.2 on August 25, 1909. 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 2 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 44 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 51,679 recorded deaths. The most severe:
- 1703
Central Apennino, Norcia, L'Aquila, Perugia
14 Jan 1703 · 144 km away · intensity XI
40,000 deathsExtreme damage ($25M+)
- 1703M6.7
L'Aquila (Aquila)
2 Feb 1703 · 170 km away · intensity XI
10,000 deathsSevere damage ($5–24M)tsunami
- 1887M6.5
Ligurian Coast
23 Feb 1887 · 283 km away · intensity X
600 deathsSevere damage ($5–24M)
- 1789
Citta Di Castello,Sansepolcro
30 Sep 1789 · 55 km away · intensity X
500 deathsSevere damage ($5–24M)
- 1730
Norcia
12 May 1730 · 135 km away · intensity X
200 deathsSevere damage ($5–24M)
- 1768
Santa Sofia
19 Oct 1768 · 77 km away · intensity X
120 deathsSevere damage ($5–24M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.