All earthquakes
1.1
very light
EARTHQUAKE DETAILS

18 km West of Acceglio

83 months ago · 22 Oct, 07:12

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 39% of Italian events in the past year

Where

18 km West of AcceglioEarthquakes 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

6 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.7kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×708 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 ≈ 32 s

Animation sped up ~6× compared to reality.

  • Cuneo
    65 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Moncalieri
    91 km from the epicentre
    first tremor in ~15 s
    main shaking in ~26 s
  • Torino
    99 km from the epicentre
    first tremor in ~17 s
    main shaking in ~28 s
  • Sanremo
    112 km from the epicentre
    first tremor in ~19 s
    main shaking in ~32 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?

Aftershock

It is an aftershock: it follows a stronger quake (M1.8, 84 months ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

1.8
The mainshock
21 km South-West of Sauze di Cesana
84 months ago · 10 Oct, 08:37
Activity in the area right now (30 km radius)
1
last 24 hours
4
last 7 days
12
last 30 days
4 before1 after
this quake
Strongest of the sequence1.8

How often does it happen here?

about every ~16 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 270 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.

19595.4
Ubaye earthquake
5 April 1959 · 1 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19355.3
Embrunais earthquake
19 March 1935 · 18 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
18845.2
Alpi Cozie earthquake
27 November 1884 · 47 km from here
VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.
19045.1
Briançonnais earthquake
12 July 1904 · 45 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

Brianconnais

The epicentre lies about 2 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
8 km West of Acceglio
10 km East · 9 km
83 months ago
28 Oct, 02:10
1.8
84 months ago
10 Oct, 08:37
1.4
14 km West of Bellino
13 km North-East · 7 km
84 months ago
3 Oct, 08:52
1.5
14 km West of Argentera
13 km South · 10 km
84 months ago
2 Oct, 00:31
1.0
2 km South-West of Stroppo
29 km East · 10 km
84 months ago
23 Sept, 22:18

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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