All earthquakes
1.3
very light
EARTHQUAKE DETAILS

M1.3 earthquake · 1 km West of Tolmezzo (UD)

8 years ago · 15 May 2018, 06:58

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

1 km 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

18 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
    45 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Pordenone
    62 km from the epicentre
    first tremor in ~10 s
    main shaking in ~18 s
  • Trieste
    105 km from the epicentre
    first tremor in ~18 s
    main shaking in ~30 s
  • Treviso
    105 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

7 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 (M3.6, 8 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

3.6
The mainshock
3 km South of Bordano
8 years ago · 9 May 2018, 23:48
Activity in the area right now (30 km radius)
1
last 24 hours
5
last 7 days
20
last 30 days
9 before8 after
this quake
Strongest of the sequence3.6

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: 246 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 · 43 km from here
IX-XCompletely destructive: most buildings are destroyed.
19766.5
Friuli earthquake
6 May 1976 · 22 km from here
IX-XCompletely destructive: most buildings are destroyed.
15116.3
Friuli-Slovenia earthquake
26 March 1511 · 28 km from here
IXDestructive: many buildings partly or fully collapse.
19286.0
Carnia earthquake
27 March 1928 · 8 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

2.1
8 years ago
15 May 2018, 03:11
1.1
2 km South-West of Preone
16 km South-West · 11 km
8 years ago
13 May 2018, 00:58
1.1
2 km North-West of Raveo
15 km West · 7 km
8 years ago
17 May 2018, 23:21
1.1
8 years ago
10 May 2018, 11:02
3.6
3 km South of Bordano
15 km South-East · 9 km
8 years ago
9 May 2018, 23:48
1.3
3 km South of Bordano
15 km South-East · 9 km
8 years ago
9 May 2018, 23:27
0.5
8 years ago
21 May 2018, 17:21
1.5
4 km North-East of Tramonti di Sotto
19 km South-West · 10 km
8 years ago
8 May 2018, 10:25
0.9
3 km South of Bordano
16 km South-East · 8 km
8 years ago
22 May 2018, 22:43
0.8
5 km North-West of Moggio Udinese
14 km North-East · 9 km
8 years ago
3 May 2018, 01:16

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).