All earthquakes
0.3
very light
EARTHQUAKE DETAILS

1 km North-East of Issime

87 months ago · 17 Jul, 04:57

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 0% of Italian events in the past year

Where

1 km North-East of IssimeEarthquakes in the province of AostaEarthquakes in Valle d'Aosta

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.

0.1kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×11,220 its energy
M-1this quakeM1

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 ≈ 22 s

Animation sped up ~4× compared to reality.

  • Novara
    65 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Torino
    67 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Gallarate
    73 km from the epicentre
    first tremor in ~12 s
    main shaking in ~21 s
  • Varese
    76 km from the epicentre
    first tremor in ~13 s
    main shaking in ~22 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 (~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 (M1.1, 87 months ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

1.1
The mainshock
1 km North-West of Issime
87 months ago · 17 Jul, 04:10
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
0
last 30 days
1 before1 after
this quake
Strongest of the sequence1.1

How often does it happen here?

about every ~4 months

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 37 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.

18925.0
Valle d'Aosta earthquake
5 March 1892 · 14 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19684.9
Valle d'Aosta earthquake
18 June 1968 · 7 km from here
VIStrong: felt by everyone, many get scared; objects fall, first light damage to buildings.
19124.7
Canavese earthquake
31 May 1912 · 17 km from here
V-VIStrong: felt by everyone, many get scared; objects fall, first light damage to buildings.
19364.5
Biellese earthquake
17 October 1936 · 21 km from here
VI-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 Monferrato

The epicentre lies about 57 km from Western Monferrato, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.4between 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

1.1
1 km North-West of Issime
2 km West · 8 km
87 months ago
17 Jul, 04:10
1.0
3 km North of Issogne
16 km West · 9 km
87 months ago
17 Jul, 09:15

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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