All earthquakes
0.8
very light
EARTHQUAKE DETAILS

M0.8 earthquake · 2 km West of Zuglio (UD)

8 years ago · 23 Nov 2017, 03:55

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 17% of Italian events in the past year

Where

2 km West of ZuglioEarthquakes 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

20 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.2kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×1,995 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 ≈ 32 s

Animation sped up ~6× compared to reality.

  • Udine
    50 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • Pordenone
    64 km from the epicentre
    first tremor in ~11 s
    main shaking in ~18 s
  • Treviso
    106 km from the epicentre
    first tremor in ~18 s
    main shaking in ~30 s
  • Trieste
    111 km from the epicentre
    first tremor in ~19 s
    main shaking in ~32 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

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?

Aftershock

It is an aftershock: it follows a stronger quake (M2.2, 8 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.2
The mainshock
4 km North of Resiutta
8 years ago · 22 Nov 2017, 00:39
Activity in the area right now (30 km radius)
3
last 24 hours
7
last 7 days
23
last 30 days
5 before14 after
this quake
Strongest of the sequence2.2

How often does it happen here?

about every ~18 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 237 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 · 47 km from here
IX-XCompletely destructive: most buildings are destroyed.
19766.5
Friuli earthquake
6 May 1976 · 28 km from here
IX-XCompletely destructive: most buildings are destroyed.
15116.3
Friuli-Slovenia earthquake
26 March 1511 · 34 km from here
IXDestructive: many buildings partly or fully collapse.
19286.0
Carnia earthquake
27 March 1928 · 11 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 lies about 4 km from But-Chiarso, one of the seismic structures mapped by INGV geologists.

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

2.2
4 km North of Resiutta
20 km East · 11 km
8 years ago
22 Nov 2017, 00:39
1.2
4 km South-West of Verzegnis
15 km South · 13 km
8 years ago
25 Nov 2017, 16:51
1.2
3 km North of Tramonti di Sotto
21 km South-West · 10 km
8 years ago
18 Nov 2017, 19:58
1.1
3 km North of Tramonti di Sotto
21 km South-West · 10 km
8 years ago
28 Nov 2017, 11:14
1.8
5 km North of Resiutta
19 km East · 15 km
8 years ago
28 Nov 2017, 19:13
0.6
4 km North-West of Raveo
12 km West · 4 km
8 years ago
28 Nov 2017, 21:57
1.2
3 km North-East of Gemona del Friuli
25 km South-East · 10 km
8 years ago
29 Nov 2017, 07:56
1.1
2 km North of Preone
13 km South-West · 7 km
8 years ago
16 Nov 2017, 23:51
2.1
2 km North-East of Preone
12 km South-West · 6 km
8 years ago
16 Nov 2017, 23:50
0.4
3 km South of Amaro
15 km South-East · 1 km
8 years ago
30 Nov 2017, 20:15

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).