All earthquakes
0.6
very light
EARTHQUAKE DETAILS

M0.6 earthquake · 4 km North-West of Ollomont (AO)

6 years ago · 19 Jul 2020, 23:43

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 7% of Italian events in the past year

Where

4 km North-West of OllomontEarthquakes 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

10 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.1kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×3,981 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 ≈ 34 s

Animation sped up ~6× compared to reality.

  • Torino
    97 km from the epicentre
    first tremor in ~16 s
    main shaking in ~28 s
  • Moncalieri
    110 km from the epicentre
    first tremor in ~18 s
    main shaking in ~31 s
  • Novara
    116 km from the epicentre
    first tremor in ~19 s
    main shaking in ~33 s
  • Varese
    119 km from the epicentre
    first tremor in ~20 s
    main shaking in ~34 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

7 km
shallow

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

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?

Aftershock

It is an aftershock: it follows a stronger quake (M3.4, 6 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

3.4
The mainshock
21 km North of Courmayeur
6 years ago · 23 Jun 2020, 08:25
Activity in the area right now (30 km radius)
0
last 24 hours
11
last 7 days
32
last 30 days
3 before6 after
this quake
Strongest of the sequence3.4

How often does it happen here?

about every ~32 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 133 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.

19465.8
Vallese, Sierre earthquake
25 January 1946 · 50 km from here
15245.8
Vallese, Ardon earthquake
April 1524 · 40 km from here
19465.5
Vallese, Sierre earthquake
30 May 1946 · 44 km from here
18175.4
Massif du Mont-Blanc earthquake
11 March 1817 · 43 km from here
VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.

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

The closest seismic structure

Chamonix

The epicentre lies about 21 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

0.7
5 km North-West of Ollomont
1 km North-West · 8 km
6 years ago
19 Jul 2020, 22:03
1.2
20 km North-West of Bionaz
22 km North-East · 9 km
6 years ago
23 Jul 2020, 23:59
1.5
Confine Italia-Svizzera (SVIZZERA)
25 km North-West · 9 km
6 years ago
28 Jul 2020, 00:43
0.9
6 years ago
1 Aug 2020, 21:51
1.7
20 km North of Courmayeur
28 km West · 10 km
6 years ago
9 Aug 2020, 01:10
1.5
2 km North-East of Avise
23 km South-West · 6 km
6 years ago
24 Jun 2020, 02:00
3.4
21 km North of Courmayeur
26 km West · 9 km
6 years ago
23 Jun 2020, 08:25
1.1
5 km North-West of Bionaz
16 km East · 8 km
6 years ago
15 Aug 2020, 21:12
0.5
7 km North of Bionaz
17 km East · 10 km
6 years ago
18 Aug 2020, 04:56

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).