All earthquakes
1.7
very light
EARTHQUAKE DETAILS

M1.7 earthquake · 3 km North-West of Pradleves (CN)

6 years ago · 14 Aug 2020, 11:02

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

Stronger than 78% of Italian events in the past year

Where

3 km North-West of PradlevesEarthquakes 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

18 events
Magnitude:lightweakmoderatestrong

The energy released

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

5.4kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×89 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
    25 km from the epicentre
    first tremor in ~5 s
    main shaking in ~8 s
  • Moncalieri
    70 km from the epicentre
    first tremor in ~12 s
    main shaking in ~20 s
  • Sanremo
    80 km from the epicentre
    first tremor in ~13 s
    main shaking in ~23 s
  • Torino
    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

12 km
medium depth
1.3 times the height of Mount Everest

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

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?

Foreshock

In hindsight it was a foreshock: 6 years 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
3 km North of San Damiano Macra
6 years ago · 1 Sept 2020, 02:21
Activity in the area right now (30 km radius)
0
last 24 hours
7
last 7 days
28
last 30 days
5 before12 after
this quake
Strongest of the sequence2.0

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: 284 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.

15645.8
Lantosque earthquake
20 July 1564 · 46 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
18085.6
Val Pellice earthquake
2 April 1808 · 45 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19595.4
Ubaye earthquake
5 April 1959 · 39 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
18085.3
Val Pellice earthquake
16 April 1808 · 46 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

Brianconnais

The epicentre lies about 21 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

0.6
3 km South-West of Casteldelfino
21 km North-West · 11 km
6 years ago
14 Aug 2020, 01:13
1.3
5 km East of Demonte
14 km South-East · 12 km
6 years ago
15 Aug 2020, 13:32
1.1
3 km South of Monterosso Grana
11 km South-East · 11 km
6 years ago
16 Aug 2020, 15:33
1.1
3 km South-West of Monterosso Grana
10 km South-East · 11 km
6 years ago
17 Aug 2020, 12:45
0.9
2 km South-West of Robilante
28 km South-East · 8 km
6 years ago
21 Aug 2020, 11:26
1.2
6 years ago
5 Aug 2020, 10:02
1.5
4 km East of Demonte
12 km South-East · 11 km
6 years ago
25 Aug 2020, 03:57
1.2
5 km South-East of Demonte
16 km South-East · 15 km
6 years ago
27 Aug 2020, 04:58
2.0
6 years ago
1 Sept 2020, 02:21
0.6
3 km North of Cartignano
9 km North-East · 7 km
6 years ago
1 Sept 2020, 02:38

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).