All earthquakes
1.5
very light
EARTHQUAKE DETAILS

1 km South-East of Cortemilia

18 months ago · 23 Feb, 08:32

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

Stronger than 68% of Italian events in the past year

Where

1 km South-East of CortemiliaEarthquakes 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

24 events
Magnitude:lightweakmoderatestrong

The energy released

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

2.7kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×178 its energy
M1this quakeM3

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 ≈ 15 s

Animation sped up ~3× compared to reality.

  • Savona
    35 km from the epicentre
    first tremor in ~6 s
    main shaking in ~10 s
  • Asti
    38 km from the epicentre
    first tremor in ~7 s
    main shaking in ~11 s
  • Alessandria
    50 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • Genova
    53 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 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
medium depth
1.1 times the height of Mount Everest

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

in line with the area average (~9 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: 18 months ago the same area had a stronger quake (M2.0). This can only be said after the fact — it was not predictable beforehand.

2.0
The mainshock
1 km South of Cortemilia
18 months ago · 28 Feb, 08:40
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
0
last 30 days
2 before21 after
this quake
Strongest of the sequence2.0

How often does it happen here?

about every ~5 months

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 28 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.

16805.1
Valle Scrivia earthquake
30 April 1680 · 49 km from here
VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.
17675.0
Genovese earthquake
7 February 1767 · 37 km from here
VI-VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.
20004.9
Monferrato earthquake
21 August 2000 · 40 km from here
VIStrong: felt by everyone, many get scared; objects fall, first light damage to buildings.
13694.9
Alessandria earthquake
1 February 1369 · 50 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

Southern Piemonte

The epicentre lies about 39 km from Southern Piemonte, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.3between 2 and 8 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

0.8
18 months ago
23 Feb, 09:53
1.7
1 km North-West of Cortemilia
2 km North-West · 14 km
18 months ago
25 Feb, 10:58
1.3
18 months ago
26 Feb, 03:56
1.8
18 months ago
26 Feb, 03:57
1.1
1 km South of Cortemilia
1 km South-West · 9 km
18 months ago
26 Feb, 04:28
0.6
5 km South-East of Cairo Montenotte
25 km South-East · 6 km
18 months ago
20 Feb, 11:30
1.3
18 months ago
28 Feb, 06:18
1.5
18 months ago
28 Feb, 06:50
1.4
2 km North-East of Bergolo
2 km South-West · 9 km
18 months ago
28 Feb, 08:38
1.4
2 km South-West of Cortemilia
2 km South-West · 11 km
18 months ago
28 Feb, 08:39

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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