A moderate earthquake near Casamicciola, Ischia caused extreme ground shaking and up to 3,100 deaths, illustrating how shallow focal depth magnifies destruction.
Key Facts
- Date and Time
- 28 July 1883, 20:25 local time (CET)
- Estimated Magnitude
- 4.2–5.5 Mw
- Mercalli Intensity
- XI (Extreme)
- Death Toll Range
- 2,313–3,100 people killed
- Homes Destroyed in Casamicciola
- 80 percent
By the Numbers
Location
Cause → Event → Consequence
A shallow-focus seismic event struck beneath the island of Ischia in the Gulf of Naples. Despite its moderate estimated moment magnitude of 4.2–5.5, the earthquake's exceptionally shallow focal depth caused dramatically amplified ground shaking at the surface, far exceeding what would normally be expected for a tremor of this size.
On 28 July 1883 at 20:25 local time, the earthquake struck Ischia, producing shaking rated XI (Extreme) on the Modified Mercalli intensity scale. The town of Casamicciola bore the brunt of destruction, with 80 percent of all homes leveled. Between 2,313 and 3,100 people perished in one of Italy's most disproportionately lethal seismic events relative to magnitude.
The catastrophic loss of life and near-total destruction of Casamicciola drew international attention to the dangers posed by shallow-focus earthquakes even of moderate magnitude. The disaster prompted reassessment of seismic risk on the volcanic island and contributed to broader scientific interest in the relationship between focal depth and surface intensity of earthquakes.
Human Cost
Each dot represents approximately 10,000 deaths. Total estimated: 2,313 (earthquake)
Range: 2,313 – 3,100