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2.0
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EARTHQUAKE DETAILS

M2.0 earthquake · 4 km East of Tolmezzo (UD)

8 years ago · 19 Jan 2018, 18:48

A light earthquake, rarely felt by people. At only a few km deep the shaking is felt more sharply at the surface.

Stronger than 88% of Italian events in the past year

Where

4 km East 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

23 events
Magnitude:lightweakmoderatestrong

The energy released

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

15kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×32 its energy
M1this quakeM3

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 ≈ 31 s

Animation sped up ~6× compared to reality.

  • Udine
    42 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Pordenone
    64 km from the epicentre
    first tremor in ~11 s
    main shaking in ~18 s
  • Trieste
    102 km from the epicentre
    first tremor in ~17 s
    main shaking in ~29 s
  • Treviso
    107 km from the epicentre
    first tremor in ~18 s
    main shaking in ~31 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 (M3.9, 8 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

3.9
The mainshock
2 km South-East of Tolmezzo
8 years ago · 19 Jan 2018, 18:39
Activity in the area right now (30 km radius)
3
last 24 hours
7
last 7 days
21
last 30 days
7 before15 after
this quake
Strongest of the sequence3.9

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: 251 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 · 39 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 · 26 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 5 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

3.9
8 years ago
19 Jan 2018, 18:39
1.3
0 km North-East of Trasaghis
14 km South-West · 10 km
8 years ago
21 Jan 2018, 09:51
1.2
1 km North-West of Tolmezzo
4 km West · 14 km
8 years ago
21 Jan 2018, 10:09
1.0
1 km North-East of Trasaghis
14 km South-West · 8 km
8 years ago
22 Jan 2018, 01:27
1.5
3 km North-West of Dogna
15 km East · 9 km
8 years ago
23 Jan 2018, 19:11
1.0
1 km East of Trasaghis
15 km South · 11 km
8 years ago
23 Jan 2018, 22:42
0.7
6 km North-West of Vito d'Asio
20 km South-West · 10 km
8 years ago
24 Jan 2018, 23:46
1.6
7 km North-West of Vito d'Asio
19 km South-West · 9 km
8 years ago
25 Jan 2018, 22:40
1.5
2 km West of Sutrio
15 km North-West · 8 km
8 years ago
26 Jan 2018, 04:38
0.8
5 km West of Ovaro
23 km West · 9 km
8 years ago
29 Jan 2018, 15:10

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).