All earthquakes
1.0
very light
EARTHQUAKE DETAILS

2 km North-East of Stroppo

109 months ago · 21 Sept, 13:50

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 30% of Italian events in the past year

Where

2 km North-East of StroppoEarthquakes 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

48 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.5kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×1,000 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
    34 km from the epicentre
    first tremor in ~6 s
    main shaking in ~10 s
  • Moncalieri
    67 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Torino
    78 km from the epicentre
    first tremor in ~13 s
    main shaking in ~22 s
  • Sanremo
    92 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

10 km
shallow
1.1 times the height of Mount Everest

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 (M2.4, 109 months ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.4
The mainshock
2 km North of Sampeyre
109 months ago · 5 Sept, 06:34
Activity in the area right now (30 km radius)
0
last 24 hours
3
last 7 days
17
last 30 days
24 before23 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: 290 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 · 30 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 · 45 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 13 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

2.1
5 km South-West of Canosio
18 km South-West · 7 km
109 months ago
21 Sept, 05:17
0.8
2 km East of Dronero
19 km East · 5 km
109 months ago
22 Sept, 03:31
1.2
1 km South-West of Paesana
18 km North-East · 12 km
109 months ago
20 Sept, 15:02
1.0
5 km South-West of Acceglio
20 km West · 14 km
108 months ago
27 Sept, 02:58
1.5
2 km East of Pradleves
17 km South-East · 11 km
109 months ago
15 Sept, 17:00
1.5
1 km North-East of Monterosso Grana
21 km South-East · 12 km
109 months ago
12 Sept, 11:52
1.5
1 km West of Monterosso Grana
20 km South-East · 11 km
109 months ago
12 Sept, 11:51
1.2
0 km South-East of Monterosso Grana
21 km South-East · 11 km
108 months ago
1 Oct, 08:46
0.3
5 km South of Paesana
14 km North-East · 11 km
108 months ago
1 Oct, 14:28
0.7
2 km North of Monterosso Grana
20 km South-East · 10 km
108 months ago
3 Oct, 02:09

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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