All earthquakes
0.6
very light
EARTHQUAKE DETAILS

M0.6 earthquake · 2 km East of Arta Terme (UD)

5 years ago · 16 Apr 2021, 04:16

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 7% of Italian events in the past year

Where

2 km East of Arta TermeEarthquakes 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

22 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.1kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×3,981 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
    48 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Pordenone
    69 km from the epicentre
    first tremor in ~12 s
    main shaking in ~20 s
  • Trieste
    108 km from the epicentre
    first tremor in ~18 s
    main shaking in ~31 s
  • Treviso
    112 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

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?

Aftershock

It is an aftershock: it follows a stronger quake (M1.5, 5 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

1.5
The mainshock
3 km West of Ampezzo
5 years ago · 27 Mar 2021, 16:22
Activity in the area right now (30 km radius)
3
last 24 hours
7
last 7 days
20
last 30 days
17 before4 after
this quake
Strongest of the sequence1.5

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: 244 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 · 38 km from here
IX-XCompletely destructive: most buildings are destroyed.
19766.5
Friuli earthquake
6 May 1976 · 27 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.
19286.0
Carnia earthquake
27 March 1928 · 14 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

0.8
3 km South-West of Lusevera
26 km South-East · 9 km
5 years ago
21 Apr 2021, 05:59
0.3
2 km South-West of Bordano
18 km South · 5 km
5 years ago
6 Apr 2021, 00:06
0.4
2 km North-West of Preone
20 km South-West · 7 km
5 years ago
27 Apr 2021, 01:08
0.8
1 km South-East of Preone
20 km South-West · 10 km
5 years ago
4 Apr 2021, 16:38
0.6
6 km North-East of Paluzza
15 km North · 11 km
5 years ago
3 Apr 2021, 02:17
1.1
3 km North-East of Preone
18 km South-West · 11 km
5 years ago
31 Mar 2021, 15:48
0.7
3 km West of Enemonzo
20 km West · 5 km
5 years ago
1 May 2021, 17:32
1.4
2 km West of Gemona del Friuli
22 km South · 10 km
5 years ago
4 May 2021, 01:29
0.8
2 km East of Villa Santina
13 km South-West · 11 km
5 years ago
27 Mar 2021, 17:21
0.7
3 km East of Villa Santina
12 km South-West · 11 km
5 years ago
27 Mar 2021, 17:09

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).