All earthquakes
3.2
weak
EARTHQUAKE DETAILS

4 km East of Cannalonga

21 days ago · 3 Aug, 20:11

A weak earthquake, felt by some of the population. Being deep, it is felt less at the surface.

Stronger than 98% of Italian events in the past year

Where

4 km East of CannalongaEarthquakes in the province of SalernoEarthquakes 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

10 events
Magnitude:lightweakmoderatestrong

The energy released

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

952kgof TNT equivalent
4.0 lightning bolts
M3
×2 the energy of a magnitude 3 earthquake
M2this quakeM4

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 ≈ 83 s

Animation sped up ~16× compared to reality.

  • Battipaglia
    51 km from the epicentre
    first tremor in ~48 s
    main shaking in ~82 s
  • Potenza
    58 km from the epicentre
    first tremor in ~48 s
    main shaking in ~82 s
  • Salerno
    67 km from the epicentre
    first tremor in ~48 s
    main shaking in ~83 s
  • Cava de' Tirreni
    75 km from the epicentre
    first tremor in ~49 s
    main shaking in ~83 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

281 km
deep
32 times the height of Mount Everest

Being deep, it is felt less at the surface.

deeper than the area average (~17 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?

Mainshock

It is the strongest quake of its sequence: so far it has been followed by 2 aftershocks within 30 km. Aftershocks tend to fade in number and strength over time.

Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
6
last 30 days
7 before2 after
nowthis quake
Strongest of the sequence1.6

How often does it happen here?

about every ~4 months

Within 50 km of this epicentre, a magnitude ≥ 3 earthquake has occurred on average this often: 32 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.

18577.1
Basilicata earthquake
16 December 1857 · 42 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
15616.7
Vallo di Diano earthquake
19 August 1561 · 36 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
15616.3
Vallo di Diano earthquake
31 July 1561 · 44 km from here
IX-XCompletely destructive: most buildings are destroyed.
19775.9
Golfo di Policastro earthquake
30 December 1977 · 32 km from here

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

The closest seismic structure

Irpinia-Agri Valley

The epicentre lies about 30 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

1.3
3 km North-West of Casaletto Spartano
23 km South-East · 20 km
21 days ago
4 Aug, 06:43
0.9
1 km North-East of Ispani
25 km South-East · 10 km
26 days ago
30 Jul, 08:00
1.1
2 km North-West of Sala Consilina
25 km North-East · 18 km
26 days ago
30 Jul, 06:49
0.7
26 days ago
29 Jul, 20:52
1.6
1 month ago
23 Jul, 06:07
1.1
1 month ago
22 Jul, 07:58
0.7
2 km West of Roccagloriosa
13 km South-East · 9 km
1 month ago
17 Jul, 07:52
0.9
4 km North-East of Ottati
29 km North · 13 km
4 days ago
21 Aug, 09:09
0.7
3 km North of Sacco
17 km North · 9 km
2 months ago
11 Jul, 19:10

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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