All earthquakes
1.3
very light
EARTHQUAKE DETAILS

7 km East of Cogne

110 months ago · 20 Aug, 08:04

A very light earthquake, probably not felt by people. At this depth the shaking is felt, but rarely causes damage.

Stronger than 55% of Italian events in the past year

Where

7 km East of CogneEarthquakes in the province of AostaEarthquakes in Valle d'Aosta

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

16 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 ≈ 28 s

Animation sped up ~5× compared to reality.

  • Torino
    59 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • Moncalieri
    72 km from the epicentre
    first tremor in ~12 s
    main shaking in ~21 s
  • Novara
    91 km from the epicentre
    first tremor in ~15 s
    main shaking in ~26 s
  • Asti
    96 km from the epicentre
    first tremor in ~16 s
    main shaking in ~28 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

11 km
medium depth
1.2 times the height of Mount Everest

At this depth the shaking is felt, but rarely causes damage.

in line with the area average (~10 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 9 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
0
last 7 days
0
last 30 days
6 before9 after
this quake
Strongest of the sequence1.2

How often does it happen here?

about every ~53 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 80 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.

17675.1
Valli di Lanzo earthquake
26 May 1767 · 36 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
18925.0
Valle d'Aosta earthquake
5 March 1892 · 26 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19684.9
Valle d'Aosta earthquake
18 June 1968 · 26 km from here
VIStrong: felt by everyone, many get scared; objects fall, first light damage to buildings.
19124.7
Canavese earthquake
31 May 1912 · 26 km from here
V-VIStrong: felt by everyone, many get scared; objects fall, first light damage to buildings.

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

The closest seismic structure

Chamonix

The epicentre lies about 53 km from Chamonix, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.0between 3 and 15 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

1.2
8 km West of Champorcher
1 km North-East · 13 km
110 months ago
20 Aug, 10:14
0.6
8 km East of Cogne
0 km South-East · 11 km
110 months ago
19 Aug, 16:28
1.1
8 km East of Cogne
1 km North-East · 12 km
110 months ago
19 Aug, 04:09
0.7
8 km South-West of Fénis
2 km North · 11 km
110 months ago
19 Aug, 03:53
0.6
7 km East of Cogne
0 km North-West · 12 km
110 months ago
19 Aug, 00:26
0.6
8 km East of Cogne
1 km North-East · 11 km
110 months ago
24 Aug, 16:03
0.5
2 km West of Issime
30 km East · 9 km
109 months ago
30 Aug, 00:19
0.7
0 km South-West of Donnas
23 km East · 17 km
109 months ago
3 Sept, 13:46
0.4
2 km South of Chialamberto
28 km South-West · 11 km
109 months ago
3 Sept, 19:07
0.5
3 km South-East of Brusson
29 km North-East · 10 km
110 months ago
4 Aug, 08:58

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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