All earthquakes
1.9
very light
EARTHQUAKE DETAILS

3 km South of Rorà

6 months ago · 23 Feb, 21:53

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 85% of Italian events in the past year

Where

3 km South of RoràEarthquakes 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

11 events
Magnitude:lightweakmoderatestrong

The energy released

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

11kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×45 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 ≈ 24 s

Animation sped up ~4× compared to reality.

  • Cuneo
    47 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Moncalieri
    47 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Torino
    56 km from the epicentre
    first tremor in ~10 s
    main shaking in ~16 s
  • Asti
    82 km from the epicentre
    first tremor in ~14 s
    main shaking in ~24 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 (~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 (M2.1, 6 months ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.1
The mainshock
5 km North-West of Bellino
6 months ago · 13 Feb, 05:22
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
10
last 30 days
2 before8 after
this quake
Strongest of the sequence2.1

How often does it happen here?

about every ~14 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 294 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 · 11 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19595.4
Ubaye earthquake
5 April 1959 · 42 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
18085.3
Val Pellice earthquake
16 April 1808 · 14 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 · 47 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

Western Piemonte

The epicentre lies about 6 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

1.8
3 km East of Rorà
3 km North-East · 11 km
6 months ago
23 Feb, 23:40
1.7
3 km South of Lusernetta
5 km East · 12 km
6 months ago
23 Feb, 19:26
0.9
1 km South-East of Pomaretto
22 km North · 5 km
6 months ago
25 Feb, 07:33
0.8
2 km East of Rorà
3 km North-East · 11 km
6 months ago
26 Feb, 13:52
1.7
6 months ago
4 Mar, 03:14
2.1
5 km North-West of Bellino
23 km South-West · 11 km
6 months ago
13 Feb, 05:22
1.0
5 km North-East of Sampeyre
15 km South · 14 km
6 months ago
8 Mar, 06:10
1.5
3 km South-East of Bellino
26 km South-West · 11 km
5 months ago
22 Mar, 02:18
1.1
4 km North-East of Sampeyre
15 km South · 14 km
5 months ago
23 Mar, 14:06
1.6
2 km North of Oncino
8 km South · 10 km
5 months ago
23 Mar, 20:59

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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