All earthquakes
1.5
very light
EARTHQUAKE DETAILS

M1.5 earthquake · 2 km North-West of Argentera (CN)

7 years ago · 20 Jul 2019, 14:30

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 69% of Italian events in the past year

Where

2 km North-West of ArgenteraEarthquakes 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

27 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 ≈ 29 s

Animation sped up ~5× compared to reality.

  • Cuneo
    49 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Moncalieri
    89 km from the epicentre
    first tremor in ~15 s
    main shaking in ~26 s
  • Sanremo
    91 km from the epicentre
    first tremor in ~15 s
    main shaking in ~26 s
  • Torino
    100 km from the epicentre
    first tremor in ~17 s
    main shaking in ~29 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
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 (~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: 7 years ago the same area had a stronger quake (M2.4). This can only be said after the fact — it was not predictable beforehand.

2.4
The mainshock
3 km North-West of Argentera
7 years ago · 21 Jul 2019, 17:40
Activity in the area right now (30 km radius)
0
last 24 hours
7
last 7 days
15
last 30 days
7 before19 after
this quake
Strongest of the sequence2.4

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: 282 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 · 49 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
19595.4
Ubaye earthquake
5 April 1959 · 20 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19355.3
Embrunais earthquake
19 March 1935 · 39 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19385.1
Queyras earthquake
18 July 1938 · 37 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 6 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

1.8
7 years ago
20 Jul 2019, 14:18
1.1
3 km East of Argentera
5 km East · 10 km
7 years ago
20 Jul 2019, 06:12
2.2
7 years ago
19 Jul 2019, 23:16
1.0
1 km West of Argentera
1 km South-East · 10 km
7 years ago
21 Jul 2019, 09:42
1.4
7 years ago
19 Jul 2019, 14:37
2.0
7 years ago
21 Jul 2019, 16:36
1.0
5 km East of Argentera
6 km East · 11 km
7 years ago
21 Jul 2019, 16:53
2.4
3 km North-West of Argentera
2 km North-East · 10 km
7 years ago
21 Jul 2019, 17:40
0.9
18 km West of Argentera
17 km West · 13 km
7 years ago
19 Jul 2019, 01:09
1.8
9 km West of Argentera
9 km South-West · 10 km
7 years ago
18 Jul 2019, 18:52

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).