M6.3 earthquake 3 km SE of Sassa, Italy

Monday, April 6, 2009, 01:32:39 UTC · 42.334°N, 13.334°E

A magnitude 6.3 earthquake struck 3 km SE of Sassa, Italy on Monday, April 6, 2009, 01:32:39 UTC, at a depth of 8.8 km (shallow). USGS received 837 “Did You Feel It?” reports, with a maximum reported intensity of VIII (severe). It is the strongest earthquake within 300 km since an M6.9 on November 23, 1980.

Magnitude: 6.3; Strong · mwc
Depth: 9 km; Shallow
Felt reports: 837; Max intensity VIII
Est. shaking: VIII; Severe (ShakeMap)
PAGER alert: None; Not issued
Tsunami: No flag; USGS feed

Outlined circle: this earthquakeDashed circle: 100 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

43 kilotons of TNT

That is about 3 times the Hiroshima bomb. It released about 89 times the energy of a magnitude 5.0.

Tectonic setting

390 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

9 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

Reports sent by people to USGS, grouped by place (most reports first). Intensity uses the Modified Mercalli scale (I–X): what people felt, not the magnitude.

Place	Intensity	Reports	Distance
Rome, Lazio, Italy	IV · Light	337	85 km
Naples, Campania, Italy	IV · Light	34	182 km
Pescara, Abruzzen, Italy	V · Moderate	28	73 km
LʿAquila, Abruzzen, Italy	VIII · Severe	17	10 km
Florence, Toscana, Italy	IV · Light	11	234 km
Chieti, Abruzzen, Italy	VI · Strong	10	68 km
Terni, Umbria, Italy	V · Moderate	10	62 km
Perugia, Umbria, Italy	III · Weak	8	116 km
Teramo, Abruzzen, Italy	V · Moderate	6	48 km
Latina, Lazio, Italy	IV · Light	6	103 km
Pesaro, Marken, Italy	IV · Light	5	179 km
Pozzuoli, Campania, Italy	III · Weak	5	179 km

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 100 km

USGS lists 32 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M5.5 on April 7, 2009. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 123 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 109 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 103,005 recorded deaths. The most severe:

1703
Central Apennino, Norcia, L'Aquila, Perugia
14 Jan 1703 · 53 km away · intensity XI
40,000 deathsExtreme damage ($25M+)
1915M7.5
Marsica, Avezzano, Abruzzi
13 Jan 1915 · 40 km away · intensity XI
29,978 deaths$60 million damage
1703M6.7
L'Aquila (Aquila)
2 Feb 1703 · 18 km away · intensity XI
10,000 deathsSevere damage ($5–24M)tsunami
1805
Molise, Rosolone, Napoli (Naples), Isernia
26 Jul 1805 · 170 km away · intensity XI
5,600 deathsExtreme damage ($25M+)
1980M6.9
Avellino, Potenza, Caserta, Naples
23 Nov 1980 · 231 km away · intensity X
4,689 deaths$20 billion damage
1731M6.3
Foggia
20 Mar 1731 · 202 km away · intensity X
3,600 deathsSevere damage ($5–24M)tsunami

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers