All earthquakes
0.8
very light
EARTHQUAKE DETAILS

M0.8 earthquake · 3 km West of Preone (UD)

9 years ago · 17 Mar 2017, 18:54

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

3 km West 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

24 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 ≈ 30 s

Animation sped up ~6× compared to reality.

  • Udine
    45 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Pordenone
    48 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Treviso
    90 km from the epicentre
    first tremor in ~15 s
    main shaking in ~26 s
  • Venezia
    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

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 (~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: 9 years ago the same area had a stronger quake (M2.8). This can only be said after the fact — it was not predictable beforehand.

2.8
The mainshock
1 km South of Venzone
9 years ago · 23 Mar 2017, 14:11
Activity in the area right now (30 km radius)
1
last 24 hours
5
last 7 days
21
last 30 days
12 before11 after
this quake
Strongest of the sequence2.8

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: 242 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 · 24 km from here
IX-XCompletely destructive: most buildings are destroyed.
15116.3
Friuli-Slovenia earthquake
26 March 1511 · 32 km from here
IXDestructive: many buildings partly or fully collapse.
18736.3
Alpago Cansiglio earthquake
29 June 1873 · 42 km from here
IX-XCompletely destructive: most buildings are destroyed.
19366.1
Alpago Cansiglio earthquake
18 October 1936 · 46 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 3 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

0.8
3 km South-East of Preone
4 km East · 11 km
9 years ago
18 Mar 2017, 18:02
0.4
9 years ago
19 Mar 2017, 00:41
1.0
9 years ago
19 Mar 2017, 04:00
0.8
9 years ago
16 Mar 2017, 04:30
0.9
4 km West of Forni di Sotto
19 km West · 5 km
9 years ago
20 Mar 2017, 11:02
1.5
1 km South-East of Claut
25 km West · 9 km
9 years ago
14 Mar 2017, 03:11
2.8
1 km South of Venzone
25 km East · 10 km
9 years ago
23 Mar 2017, 14:11
0.9
1 km North of Ampezzo
12 km North-West · 7 km
9 years ago
11 Mar 2017, 13:46
1.8
1 km North of Preone
3 km North-East · 6 km
9 years ago
24 Mar 2017, 00:06
2.5
9 years ago
24 Mar 2017, 18:47

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).