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3.1
weak
EARTHQUAKE DETAILS

M3.1 earthquake outside Italy

1 year ago · 1 Dec 2024, 18:25

A weak earthquake, felt by some of the population. At this depth the shaking is felt, but rarely causes damage.

The strongest of the past 12 months within 50 km

Where

Nearest Italian town: Drenchia (UD)Earthquakes in the province of UdineEarthquakes in Friuli-Venezia Giulia

Epicentre abroad

The epicentre lies outside Italy's borders. The quake appears here because the INGV seismic network also records events close to Italy, which can be felt on Italian territory.

How far away could it be felt?

An estimate of how far people may have felt this quake.

  • up to ~12 km · felt only by some, at rest

The coloured rings on the map below show these distances.

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

8 events
Magnitude:lightweakmoderatestrong

The energy released

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

674kgof TNT equivalent
2.8 lightning bolts
M3
×1.4 the energy of a magnitude 3 earthquake
M2this quakeM4

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 ≈ 36 s

Animation sped up ~7× compared to reality.

  • Udine
    37 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Trieste
    53 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • Pordenone
    85 km from the epicentre
    first tremor in ~14 s
    main shaking in ~24 s
  • Treviso
    125 km from the epicentre
    first tremor in ~21 s
    main shaking in ~36 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

11 km
medium depth
1.2 times the height of Mount Everest

At this depth the shaking is felt, but rarely causes damage.

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?

Mainshock

It is the strongest quake of its sequence: so far it has been followed by one aftershock within 30 km. Aftershocks tend to fade in number and strength over time.

Activity in the area right now (30 km radius)
1
last 24 hours
1
last 7 days
3
last 30 days
6 before1 after
this quake
Strongest of the sequence2.6

How often does it happen here?

about every ~7 months

Within 50 km of this epicentre, a magnitude ≥ 3 earthquake has occurred on average this often: 19 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 · 45 km from here
IX-XCompletely destructive: most buildings are destroyed.
19766.5
Friuli earthquake
6 May 1976 · 49 km from here
IX-XCompletely destructive: most buildings are destroyed.
15116.3
Friuli-Slovenia earthquake
26 March 1511 · 41 km from here
IXDestructive: many buildings partly or fully collapse.
19766.0
Friuli earthquake
15 September 1976 · 47 km from here
VIII-IXDestructive: many buildings partly or fully collapse.

Source: Parametric Catalogue of Italian Earthquakes CPTI15 (INGV, CC BY 4.0).

The closest seismic structure

Tolmin-Idrija

The epicentre lies about 6 km from Tolmin-Idrija, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.2between 1 and 14 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

2.0
6 km South-East of Stregna
4 km West · 11 km
1 year ago
1 Dec 2024, 18:15
1.2
11 km South-East of Stregna
6 km South-West · 7 km
1 year ago
28 Nov 2024, 09:59
1.3
5 km North of Pulfero
23 km North-West · 7 km
1 year ago
26 Nov 2024, 13:08
1.0
6 km North of Pulfero
25 km North-West · 10 km
1 year ago
11 Dec 2024, 20:38
1.3
14 km North-East of Drenchia
19 km North · 8 km
1 year ago
17 Nov 2024, 23:49
2.6
12 km North-East of Gorizia
10 km South · 10 km
1 year ago
16 Nov 2024, 08:24
1.6
Confine Italia-Slovenia (SLOVENIA)
25 km East · 7 km
1 year ago
15 Nov 2024, 03:19

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).