All earthquakes
0.6
very light
EARTHQUAKE DETAILS

8 km West of Pontechianale

106 months ago · 7 Dec, 01:39

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 6% of Italian events in the past year

Where

8 km West of PontechianaleEarthquakes 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

17 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 ≈ 30 s

Animation sped up ~6× compared to reality.

  • Cuneo
    57 km from the epicentre
    first tremor in ~10 s
    main shaking in ~16 s
  • Moncalieri
    69 km from the epicentre
    first tremor in ~12 s
    main shaking in ~20 s
  • Torino
    77 km from the epicentre
    first tremor in ~13 s
    main shaking in ~22 s
  • Asti
    104 km from the epicentre
    first tremor in ~18 s
    main shaking in ~30 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

8 km
shallow

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

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: 106 months ago the same area had a stronger quake (M2.9). This can only be said after the fact — it was not predictable beforehand.

2.9
The mainshock
21 km South-West of Claviere
106 months ago · 19 Dec, 10:10
Activity in the area right now (30 km radius)
0
last 24 hours
2
last 7 days
13
last 30 days
8 before8 after
this quake
Strongest of the sequence2.9

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: 275 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 · 31 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19595.4
Ubaye earthquake
5 April 1959 · 22 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
18085.3
Val Pellice earthquake
16 April 1808 · 36 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 · 25 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 10 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

1.5
5 km North of Acceglio
17 km South · 11 km
106 months ago
7 Dec, 00:03
1.6
5 km North of Acceglio
17 km South · 11 km
106 months ago
3 Dec, 23:33
2.1
16 km West of Bellino
18 km South-West · 11 km
106 months ago
12 Dec, 12:00
1.5
3 km North-East of Bellino
10 km South-East · 11 km
106 months ago
1 Dec, 05:24
0.9
15 km West of Acceglio
28 km South-West · 14 km
106 months ago
30 Nov, 20:50
1.2
5 km South-West of Sanfront
26 km East · 9 km
106 months ago
27 Nov, 12:50
1.4
7 km West of Bellino
14 km South · 10 km
106 months ago
17 Dec, 20:43
2.9
106 months ago
19 Dec, 10:10
2.1
20 km South-West of Claviere
22 km West · 11 km
106 months ago
19 Dec, 10:45
1.0
21 km South-West of Claviere
24 km West · 10 km
106 months ago
19 Dec, 12:49

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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