All earthquakes
1.7
very light
EARTHQUAKE DETAILS

M1.7 earthquake · 20 km East of Tarvisio (UD)

2 years ago · 28 Dec 2023, 09:30

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 78% of Italian events in the past year

Where

20 km East of TarvisioEarthquakes 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

2 events
Magnitude:lightweakmoderatestrong

The energy released

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

5.4kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×89 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.

  • Gorizia
    61 km from the epicentre
    first tremor in ~10 s
    main shaking in ~18 s
  • Udine
    64 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Trieste
    93 km from the epicentre
    first tremor in ~16 s
    main shaking in ~27 s
  • Pordenone
    109 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?

Isolated quake

In the 30 days around this event no other quakes were recorded within 30 km: a one-off episode, very common in Italy.

Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
4
last 30 days
1 before0 after
this quake
Strongest of the sequence1.2

How often does it happen here?

about every ~35 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 122 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 · 21 km from here
IX-XCompletely destructive: most buildings are destroyed.
16906.2
Carinthia, Villach earthquake
4 December 1690 · 19 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
19985.6
Slovenia nord-occidentale earthquake
12 April 1998 · 24 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
18575.2
Stiria earthquake
7 March 1857 · 47 km from here
VI-VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.

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

The closest seismic structure

Jesenice

The epicentre lies about 2 km from Jesenice, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.1between 1 and 12 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

1.2
17 km North-East of Savogna
23 km South-West · 8 km
2 years ago
3 Dec 2023, 18:10

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).