All earthquakes
1.1
very light
EARTHQUAKE DETAILS

Confine Italia-Svizzera (SVIZZERA)

74 months ago · 14 Aug, 23:53

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 39% of Italian events in the past year

Where

Confine Italia-Svizzera (SVIZZERA)Earthquakes in the province of AostaEarthquakes in Valle d'Aosta

Epicentre at sea

The epicentre is at sea: for the same magnitude, the shaking is felt less on land, because the energy fades along the way before reaching the coast.

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

3 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.7kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×708 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 ≈ 38 s

Animation sped up ~7× compared to reality.

  • Varese
    118 km from the epicentre
    first tremor in ~20 s
    main shaking in ~34 s
  • Gallarate
    126 km from the epicentre
    first tremor in ~21 s
    main shaking in ~36 s
  • Novara
    131 km from the epicentre
    first tremor in ~22 s
    main shaking in ~38 s
  • Torino
    132 km from the epicentre
    first tremor in ~22 s
    main shaking in ~38 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 (~10 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 (M1.5, 74 months ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

1.5
The mainshock
Confine Italia-Svizzera (SVIZZERA)
74 months ago · 28 Jul, 00:43
Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
1
last 30 days
2 before0 after
this quake
Strongest of the sequence1.5

How often does it happen here?

about every ~36 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 118 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.

18556.2
Vallese, Stalden-Visp earthquake
25 July 1855 · 34 km from here
15845.9
Vaud, Aigle earthquake
11 March 1584 · 35 km from here
19465.8
Vallese, Sierre earthquake
25 January 1946 · 10 km from here
15245.8
Vallese, Ardon earthquake
April 1524 · 11 km from here

Source: Parametric Catalogue of Italian Earthquakes CPTI15 (INGV, CC BY 4.0).

The closest seismic structure

Western Valais

The epicentre sits above this source area: the deep structure where this area's earthquakes can originate.

estimated maximum magnitude 7.0between 3 and 15 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

1.5
Confine Italia-Svizzera (SVIZZERA)
28 km South-West · 9 km
74 months ago
28 Jul, 00:43
1.2
20 km North-West of Bionaz
20 km South · 9 km
74 months ago
23 Jul, 23:59

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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