All earthquakes
1.3
very light
EARTHQUAKE DETAILS

M1.3 earthquake · 2 km East of Coazze (TO)

11 years ago · 18 Mar 2015, 19:47

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 55% of Italian events in the past year

Where

2 km East of CoazzeEarthquakes in the province of TorinoEarthquakes 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

16 events
Magnitude:lightweakmoderatestrong

The energy released

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

1.3kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×355 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 ≈ 22 s

Animation sped up ~4× compared to reality.

  • Torino
    36 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Moncalieri
    36 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Cuneo
    74 km from the epicentre
    first tremor in ~12 s
    main shaking in ~21 s
  • Asti
    76 km from the epicentre
    first tremor in ~13 s
    main shaking in ~22 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

9 km
shallow

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

in line with the area average (~13 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 (M2.1, 11 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.1
The mainshock
1 km South-East of San Germano Chisone
11 years ago · 22 Feb 2015, 10:30
Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
3
last 30 days
8 before7 after
this quake
Strongest of the sequence2.1

How often does it happen here?

about every ~38 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 112 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 · 23 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
18085.3
Val Pellice earthquake
16 April 1808 · 22 km from here
VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.
19145.2
Torinese earthquake
26 October 1914 · 8 km from here
VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.
18865.2
Torinese earthquake
5 September 1886 · 3 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

Western Piemonte

The epicentre lies about 17 km from Western Piemonte, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.1between 1 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

1.4
4 km North-West of Varisella
23 km North-East · 14 km
11 years ago
16 Mar 2015, 06:39
0.9
1 km West of Villar Focchiardo
8 km North-West · 15 km
11 years ago
14 Mar 2015, 05:52
1.1
11 years ago
14 Mar 2015, 05:43
1.6
1 km East of Borgone Susa
9 km North · 14 km
11 years ago
11 Mar 2015, 19:32
1.4
11 years ago
10 Mar 2015, 14:58
1.5
2 km East of Viù
23 km North-East · 11 km
11 years ago
27 Mar 2015, 01:21
1.1
1 km North-East of Mattie
13 km North-West · 11 km
11 years ago
4 Mar 2015, 05:57
1.6
11 years ago
5 Apr 2015, 14:47
1.0
3 km West of Usseglio
24 km North-West · 11 km
11 years ago
6 Apr 2015, 20:58
1.6
4 km West of Usseglio
25 km North-West · 9 km
11 years ago
6 Apr 2015, 21:07

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).