All earthquakes
1.6
very light
EARTHQUAKE DETAILS

M1.6 earthquake · 1 km North-East of Tolmezzo (UD)

11 years ago · 15 May 2015, 00:39

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 74% of Italian events in the past year

Where

1 km North-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

11 events
Magnitude:lightweakmoderatestrong

The energy released

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

3.8kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×126 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
    45 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Pordenone
    64 km from the epicentre
    first tremor in ~11 s
    main shaking in ~18 s
  • Trieste
    105 km from the epicentre
    first tremor in ~18 s
    main shaking in ~30 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

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?

Aftershock

It is an aftershock: it follows a stronger quake (M2.4, 11 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.4
The mainshock
4 km East of Arta Terme
11 years ago · 30 Apr 2015, 10:41
Activity in the area right now (30 km radius)
3
last 24 hours
7
last 7 days
22
last 30 days
8 before2 after
this quake
Strongest of the sequence2.4

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 · 40 km from here
IX-XCompletely destructive: most buildings are destroyed.
19766.5
Friuli earthquake
6 May 1976 · 23 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 · 10 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 2 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

2.1
5 km North of Taipana
27 km South-East · 13 km
11 years ago
17 May 2015, 23:35
1.9
4 km North-East of Arta Terme
7 km North-East · 5 km
11 years ago
10 May 2015, 15:51
0.7
1 km East of Arta Terme
4 km North · 8 km
11 years ago
4 May 2015, 14:51
0.7
11 years ago
3 May 2015, 05:16
1.4
2 km East of Arta Terme
4 km North · 8 km
11 years ago
3 May 2015, 00:00
2.4
4 km East of Arta Terme
4 km North-East · 10 km
11 years ago
30 Apr 2015, 10:41
1.5
3 km South of Zuglio
5 km West · 5 km
11 years ago
27 Apr 2015, 13:42
0.9
5 km North-West of Cavazzo Carnico
6 km South-West · 6 km
11 years ago
5 Jun 2015, 06:51
1.2
4 km West of Chiusaforte
19 km East · 6 km
11 years ago
19 Apr 2015, 18:47
2.2
3 km West of Lusevera
21 km South-East · 10 km
11 years ago
16 Apr 2015, 06:18

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).