All earthquakes
1.6
very light
EARTHQUAKE DETAILS

M1.6 earthquake · 2 km West of Perrero (TO)

11 years ago · 13 Sept 2015, 15:18

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

Stronger than 74% of Italian events in the past year

Where

2 km West of PerreroEarthquakes 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

12 events
Magnitude:lightweakmoderatestrong

The energy released

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

3.8kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×126 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 ≈ 25 s

Animation sped up ~5× compared to reality.

  • Moncalieri
    48 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Torino
    52 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • Cuneo
    68 km from the epicentre
    first tremor in ~12 s
    main shaking in ~20 s
  • Asti
    88 km from the epicentre
    first tremor in ~15 s
    main shaking in ~25 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

13 km
medium depth
1.5 times the height of Mount Everest

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

in line with the area average (~12 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 (M3.1, 11 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

3.1
The mainshock
3 km North-East of Villar Pellice
11 years ago · 10 Sept 2015, 09:32
Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
6
last 30 days
7 before4 after
this quake
Strongest of the sequence3.1

How often does it happen here?

about every ~22 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 194 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 · 16 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
18085.3
Val Pellice earthquake
16 April 1808 · 20 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 · 49 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19145.2
Torinese earthquake
26 October 1914 · 25 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 12 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

1.2
3 km South-East of Rorà
21 km South-East · 12 km
11 years ago
11 Sept 2015, 23:12
1.1
3 km West of Torre Pellice
13 km South-East · 12 km
11 years ago
10 Sept 2015, 10:00
3.1
3 km North-East of Villar Pellice
14 km South-East · 12 km
11 years ago
10 Sept 2015, 09:32
1.5
5 km South-West of Villar Focchiardo
15 km North-East · 11 km
11 years ago
17 Sept 2015, 17:50
1.3
5 km South of Lusernetta
23 km South-East · 14 km
11 years ago
7 Sept 2015, 17:53
1.6
3 km West of Torre Pellice
12 km South-East · 12 km
11 years ago
20 Sept 2015, 12:10
1.1
2 km East of Ostana
26 km South-East · 11 km
11 years ago
22 Sept 2015, 05:33
1.2
3 km South-West of San Giorio di Susa
16 km North-East · 12 km
11 years ago
5 Sept 2015, 00:25
1.4
4 km North-East of Roure
13 km North · 9 km
11 years ago
4 Sept 2015, 21:13
1.9
1 km East of Chiusa di San Michele
26 km North-East · 11 km
11 years ago
1 Sept 2015, 15:22

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).