All earthquakes
1.3
very light
EARTHQUAKE DETAILS

4 km North-West of Calabritto

73 months ago · 3 Sept, 01:49

A very light earthquake, probably not felt by people. At only a few km deep the shaking is felt more sharply at the surface.

Stronger than 55% of Italian events in the past year

Where

4 km North-West of CalabrittoEarthquakes in the province of AvellinoEarthquakes in Campania

How far away could it be felt?

A quake this small is usually not felt by people: only seismographs record it.

Statistical estimate from the Italian intensity attenuation model (INGV): actual perception depends on geology, buildings and depth. Very shallow events can be felt locally even below the threshold.

Earthquake map

11 events
Magnitude:lightweakmoderatestrong

The energy released

How much energy this quake unleashed, translated into everyday comparisons.

1.3kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×355 its energy
M0this quakeM2

Each extra magnitude unit releases about 32 times more energy: an M5 is not "a bit stronger" than an M4 — it is a different league.

Energy estimated with the standard Gutenberg–Richter relation; an average lightning bolt ≈ 1 billion joules. Indicative values.

The race of the seismic waves

Two waves set off from the hypocentre: the faster P wave arrives first with a sharp jolt; the S wave carries the actual shaking.

P waves — the first sharp jolt (~6 km/s)S waves — the strongest shaking (~3.5 km/s)
t ≈ 11 s

Animation sped up ~2× compared to reality.

  • Battipaglia
    28 km from the epicentre
    first tremor in ~5 s
    main shaking in ~8 s
  • Avellino
    33 km from the epicentre
    first tremor in ~6 s
    main shaking in ~10 s
  • Salerno
    33 km from the epicentre
    first tremor in ~6 s
    main shaking in ~10 s
  • Cava de' Tirreni
    39 km from the epicentre
    first tremor in ~7 s
    main shaking in ~11 s

Theoretical times with average crustal speeds: real values vary with geology. The gap between P and S waves is what earthquake early-warning systems rely on.

How deep it was born

6 km
shallow

At only a few km deep the shaking is felt more sharply at the surface.

shallower than the area average (~14 km)

For the same magnitude, a shallow earthquake is felt much more than a deep one: the energy starts closer to the surface.

What kind of quake is this?

Aftershock

It is an aftershock: it follows a stronger quake (M3.0, 73 months ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

3.0
The mainshock
3 km South-East of Acerno
73 months ago · 2 Sept, 17:44
Activity in the area right now (30 km radius)
2
last 24 hours
2
last 7 days
7
last 30 days
9 before1 after
this quake
Strongest of the sequence3.0

How often does it happen here?

about every ~11 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 396 events in the last 12 years of the INGV catalogue.

An average computed on the recent past: it tells how used this area is to shaking, not when the next quake will come — earthquakes cannot be predicted.

The great earthquakes in this area's history

Almost a thousand years of catalogues: the strongest documented events within ~50 km.

19806.8
Irpinia-Basilicata earthquake
23 November 1980 · 12 km from here
XCompletely destructive: most buildings are destroyed.
17326.8
Irpinia earthquake
29 November 1732 · 30 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
16946.7
Irpinia-Basilicata earthquake
8 September 1694 · 22 km from here
XCompletely destructive: most buildings are destroyed.
15616.7
Vallo di Diano earthquake
19 August 1561 · 40 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.

Source: Parametric Catalogue of Italian Earthquakes CPTI15 (INGV, CC BY 4.0).

The closest seismic structure

Irpinia-Agri Valley

The epicentre lies about 4 km from Irpinia-Agri Valley, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.8between 1 and 14 km deep

Faults are mapped to build better and understand the territory: knowing them says nothing about when an earthquake will occur, which remains unpredictable. Source: DISS 3.3 (INGV, CC BY 4.0).

Other quakes in the area

3.0
3 km South-East of Acerno
10 km South-West · 327 km
73 months ago
2 Sept, 17:44
1.5
2 km South of Muro Lucano
27 km East · 14 km
73 months ago
2 Sept, 10:58
2.4
73 months ago
31 Aug, 20:26
1.0
3 km South-East of Morra De Sanctis
16 km North-East · 13 km
73 months ago
31 Aug, 11:05
2.0
73 months ago
29 Aug, 20:21
0.8
1 km South of Teora
9 km North-East · 10 km
73 months ago
28 Aug, 01:27
1.4
2 km North-East of San Gregorio Magno
24 km South-East · 14 km
73 months ago
10 Sept, 19:30
1.8
73 months ago
17 Aug, 23:10
1.7
3 km West of Caposele
4 km East · 15 km
73 months ago
15 Aug, 13:17
1.3
2 km South-West of Caposele
4 km East · 14 km
73 months ago
15 Aug, 13:01

Data: INGV — National Institute of Geophysics and Volcanology (CC-BY 4.0)

Estimates computed by Meteare on INGV data (Gutenberg–Richter relation; Italian macroseismic intensity attenuation model).

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