All earthquakes
1.0
very light
EARTHQUAKE DETAILS

2 km North-East of Preone

60 months ago · 29 Sept, 22:59

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 31% of Italian events in the past year

Where

2 km North-East of PreoneEarthquakes in the province of UdineEarthquakes in Friuli-Venezia Giulia

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

44 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.5kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×1,000 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 ≈ 30 s

Animation sped up ~6× compared to reality.

  • Udine
    44 km from the epicentre
    first tremor in ~7 s
    main shaking in ~13 s
  • Pordenone
    52 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • Treviso
    94 km from the epicentre
    first tremor in ~16 s
    main shaking in ~27 s
  • Trieste
    106 km from the epicentre
    first tremor in ~18 s
    main shaking in ~30 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

6 km
shallow

At only a few km deep the shaking is felt more sharply at the surface.

in line with the area average (~9 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: 59 months ago the same area had a stronger quake (M3.7). This can only be said after the fact — it was not predictable beforehand.

3.7
The mainshock
2 km East of Tolmezzo
59 months ago · 21 Oct, 02:28
Activity in the area right now (30 km radius)
1
last 24 hours
4
last 7 days
11
last 30 days
33 before10 after
this quake
Strongest of the sequence3.7

How often does it happen here?

about every ~17 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 244 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.

19766.5
Friuli earthquake
6 May 1976 · 23 km from here
IX-XCompletely destructive: most buildings are destroyed.
15116.3
Friuli-Slovenia earthquake
26 March 1511 · 31 km from here
IXDestructive: many buildings partly or fully collapse.
18736.3
Alpago Cansiglio earthquake
29 June 1873 · 46 km from here
IX-XCompletely destructive: most buildings are destroyed.
19286.0
Carnia earthquake
27 March 1928 · 6 km from here
IXDestructive: many buildings partly or fully collapse.

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

The closest seismic structure

Tramonti-Montemaggiore

The epicentre lies about 6 km from Tramonti-Montemaggiore, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.2between 1 and 6 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

1.2
5 km South of Forni di Sotto
20 km West · 10 km
60 months ago
29 Sept, 17:10
1.3
2 km West of Fanna
25 km South-West · 10 km
60 months ago
30 Sept, 06:44
1.3
4 km East of Sauris
16 km North-West · 7 km
60 months ago
29 Sept, 04:44
0.5
60 months ago
23 Sept, 20:46
2.9
2 km South-West of Venzone
20 km East · 9 km
60 months ago
23 Sept, 07:46
1.0
2 km North-West of Fanna
24 km South-West · 11 km
60 months ago
23 Sept, 05:08
1.9
2 km South of Fanna
27 km South-West · 14 km
60 months ago
22 Sept, 20:29
1.3
2 km North-East of Maniago
26 km South-West · 14 km
60 months ago
22 Sept, 10:35
1.3
2 km West of Fanna
26 km South-West · 10 km
60 months ago
22 Sept, 06:27
1.5
2 km West of Fanna
25 km South-West · 13 km
60 months ago
21 Sept, 18:56

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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