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2.4
light
EARTHQUAKE DETAILS

1 km South-East of Sant'Andrea di Conza

73 months ago · 31 Aug, 20:26

A light earthquake, rarely felt by people. At only a few km deep the shaking is felt more sharply at the surface.

Stronger than 94% of Italian events in the past year

Where

1 km South-East of Sant'Andrea di ConzaEarthquakes 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

13 events
Magnitude:lightweakmoderatestrong

The energy released

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

60kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×7.9 its energy
M1this quakeM3

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 ≈ 15 s

Animation sped up ~3× compared to reality.

  • Potenza
    42 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Battipaglia
    45 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Avellino
    50 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Salerno
    53 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 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

10 km
shallow
1.1 times the height of Mount Everest

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

in line with the area average (~15 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?

Foreshock

In hindsight it was a foreshock: 73 months ago the same area had a stronger quake (M3.0). This can only be said after the fact — it was not predictable beforehand.

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)
1
last 24 hours
1
last 7 days
7
last 30 days
6 before6 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: 379 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 · 8 km from here
XCompletely destructive: most buildings are destroyed.
17326.8
Irpinia earthquake
29 November 1732 · 36 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
16946.7
Irpinia-Basilicata earthquake
8 September 1694 · 3 km from here
XCompletely destructive: most buildings are destroyed.
15616.7
Vallo di Diano earthquake
19 August 1561 · 34 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

Conza della Campania-Tolve

The epicentre sits above this source area: the deep structure where this area's earthquakes can originate.

estimated maximum magnitude 6.5between 1 and 12 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

1.0
3 km South-East of Morra De Sanctis
10 km North-West · 13 km
73 months ago
31 Aug, 11:05
2.0
4 km East of Monteverde
25 km North-East · 17 km
73 months ago
1 Sept, 23:27
1.5
2 km South of Muro Lucano
16 km South-East · 14 km
73 months ago
2 Sept, 10:58
3.0
3 km South-East of Acerno
28 km South-West · 327 km
73 months ago
2 Sept, 17:44
2.0
73 months ago
29 Aug, 20:21
1.3
73 months ago
3 Sept, 01:49
0.8
1 km South of Teora
11 km West · 10 km
73 months ago
28 Aug, 01:27
1.4
73 months ago
10 Sept, 19:30
1.8
73 months ago
17 Aug, 23:10
1.7
3 km West of Caposele
16 km West · 15 km
73 months ago
15 Aug, 13:17

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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