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2.9
light
EARTHQUAKE DETAILS

M2.9 earthquake outside Italy

3 years ago · 15 Dec 2022, 08:19

A light earthquake, rarely felt by people. 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 ~7 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

2 events
Magnitude:lightweakmoderatestrong

The energy released

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

338kgof TNT equivalent
1.4 lightning bolts
M3
A magnitude 3 earthquake releases ×1.4 its energy
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 ≈ 41 s

Animation sped up ~8× compared to reality.

  • Gorizia
    72 km from the epicentre
    first tremor in ~12 s
    main shaking in ~21 s
  • Trieste
    79 km from the epicentre
    first tremor in ~13 s
    main shaking in ~23 s
  • Udine
    96 km from the epicentre
    first tremor in ~16 s
    main shaking in ~28 s
  • Pordenone
    143 km from the epicentre
    first tremor in ~24 s
    main shaking in ~41 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 0 aftershocks within 30 km. Aftershocks tend to fade in number and strength over time.

Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
1
last 30 days
1 before0 after
this quake
Strongest of the sequence1.9

How often does it happen here?

about every ~3 months

Within 50 km of this epicentre, a magnitude ≥ 2.5 earthquake has occurred on average this often: 43 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.

18956.0
Ljubljana earthquake
14 April 1895 · 2 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
19265.7
Carniola interna earthquake
1 January 1926 · 44 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
16915.3
Ljubljana earthquake
19 February 1691 · 5 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
16915.3
Ljubljana earthquake
10 December 1691 · 8 km from here

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

The closest seismic structure

Jesenice

The epicentre lies about 15 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

1.9
Slovenia (SLOVENIA)
11 km South-West · 8 km
3 years ago
8 Dec 2022, 13:24

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).