All earthquakes
1.3
very light
EARTHQUAKE DETAILS

4 km South-West of Tolmezzo

23 months ago · 17 Oct, 13:41

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 55% of Italian events in the past year

Where

4 km South-West of TolmezzoEarthquakes 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

27 events
Magnitude:lightweakmoderatestrong

The energy released

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

1.3kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×355 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
    43 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Pordenone
    59 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • Treviso
    102 km from the epicentre
    first tremor in ~17 s
    main shaking in ~29 s
  • Trieste
    104 km from the epicentre
    first tremor in ~17 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

5 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: 22 months ago the same area had a stronger quake (M1.6). This can only be said after the fact — it was not predictable beforehand.

1.6
The mainshock
2 km North-West of Venzone
22 months ago · 31 Oct, 13:25
Activity in the area right now (30 km radius)
0
last 24 hours
3
last 7 days
9
last 30 days
10 before16 after
this quake
Strongest of the sequence1.6

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: 247 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.

13486.6
Alpi Giulie earthquake
25 January 1348 · 45 km from here
IX-XCompletely destructive: most buildings are destroyed.
19766.5
Friuli earthquake
6 May 1976 · 20 km from here
IX-XCompletely destructive: most buildings are destroyed.
15116.3
Friuli-Slovenia earthquake
26 March 1511 · 27 km from here
IXDestructive: many buildings partly or fully collapse.
19286.0
Carnia earthquake
27 March 1928 · 5 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

But-Chiarso

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

estimated maximum magnitude 6.3between 1 and 9 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

1.3
2 km East of Sauris
25 km West · 8 km
23 months ago
17 Oct, 10:06
1.3
6 km North of Lusevera
22 km East · 10 km
23 months ago
16 Oct, 04:10
0.8
2 km South-West of Vito d'Asio
16 km South-West · 7 km
23 months ago
15 Oct, 03:33
0.8
1 km West of Lauco
9 km West · 10 km
23 months ago
21 Oct, 02:09
1.1
6 km North-East of Tramonti di Sotto
15 km South-West · 10 km
23 months ago
21 Oct, 05:33
1.1
6 km North-East of Tramonti di Sotto
15 km South-West · 9 km
22 months ago
22 Oct, 13:20
1.5
2 km South-East of Venzone
16 km South-East · 10 km
22 months ago
23 Oct, 16:39
0.7
2 km South-West of Vito d'Asio
16 km South-West · 6 km
22 months ago
23 Oct, 23:54
0.9
3 km East of Moggio Udinese
19 km East · 10 km
23 months ago
7 Oct, 13:52
1.0
2 km West of Sutrio
11 km North-West · 9 km
23 months ago
7 Oct, 09:05

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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