All earthquakes
0.8
very light
EARTHQUAKE DETAILS

M0.8 earthquake · 3 km North-East of Macra (CN)

6 years ago · 8 May 2020, 00:34

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

Stronger than 17% of Italian events in the past year

Where

3 km North-East of MacraEarthquakes in the province of CuneoEarthquakes in Piemonte

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

21 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.2kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×1,995 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 ≈ 26 s

Animation sped up ~5× compared to reality.

  • Cuneo
    30 km from the epicentre
    first tremor in ~6 s
    main shaking in ~9 s
  • Moncalieri
    65 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Torino
    76 km from the epicentre
    first tremor in ~13 s
    main shaking in ~22 s
  • Sanremo
    89 km from the epicentre
    first tremor in ~15 s
    main shaking in ~26 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

13 km
medium depth
1.4 times the height of Mount Everest

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

in line with the area average (~11 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: 6 years ago the same area had a stronger quake (M2.4). This can only be said after the fact — it was not predictable beforehand.

2.4
The mainshock
4 km North-West of Pradleves
6 years ago · 1 Jun 2020, 10:55
Activity in the area right now (30 km radius)
0
last 24 hours
7
last 7 days
30
last 30 days
12 before8 after
this quake
Strongest of the sequence2.4

How often does it happen here?

about every ~15 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 294 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.

18085.6
Val Pellice earthquake
2 April 1808 · 36 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19595.4
Ubaye earthquake
5 April 1959 · 34 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
18085.3
Val Pellice earthquake
16 April 1808 · 38 km from here
VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.
19355.3
Embrunais earthquake
19 March 1935 · 48 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.

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

The closest seismic structure

Brianconnais

The epicentre lies about 16 km from Brianconnais, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.2between 5 and 20 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

1.4
4 km South-West of Frassino
4 km North-East · 13 km
6 years ago
6 May 2020, 06:59
1.7
4 km South-West of Monterosso Grana
21 km South-East · 12 km
6 years ago
10 May 2020, 07:03
1.1
10 km North-West of Bellino
27 km North-West · 10 km
6 years ago
3 May 2020, 23:26
1.2
2 km South of Stroppo
6 km West · 10 km
6 years ago
3 May 2020, 09:54
1.9
3 km South-West of Monterosso Grana
19 km South-East · 13 km
6 years ago
3 May 2020, 04:34
2.0
1 km North of Busca
19 km East · 15 km
6 years ago
1 May 2020, 18:58
1.3
1 km West of Pradleves
12 km South-East · 16 km
6 years ago
14 May 2020, 11:33
1.3
4 km South-West of Venasca
14 km East · 10 km
6 years ago
27 Apr 2020, 03:31
2.3
4 km West of Acceglio
22 km West · 11 km
6 years ago
21 May 2020, 12:10
0.9
6 years ago
21 May 2020, 22:34

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).