All earthquakes
1.3
very light
EARTHQUAKE DETAILS

M1.3 earthquake · 3 km East of Claut (PN)

11 years ago · 13 Aug 2015, 13:29

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 55% of Italian events in the past year

Where

3 km East of ClautEarthquakes in the province of PordenoneEarthquakes 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

14 events
Magnitude:lightweakmoderatestrong

The energy released

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

1.3kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×355 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 ≈ 26 s

Animation sped up ~5× compared to reality.

  • Pordenone
    39 km from the epicentre
    first tremor in ~7 s
    main shaking in ~11 s
  • Udine
    58 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • Treviso
    74 km from the epicentre
    first tremor in ~12 s
    main shaking in ~21 s
  • Venezia
    92 km from the epicentre
    first tremor in ~15 s
    main shaking in ~26 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

6 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?

Foreshock

In hindsight it was a foreshock: 11 years ago the same area had a stronger quake (M2.7). This can only be said after the fact — it was not predictable beforehand.

2.7
The mainshock
3 km South of Erto e Casso
11 years ago · 22 Aug 2015, 14:27
Activity in the area right now (30 km radius)
0
last 24 hours
3
last 7 days
8
last 30 days
4 before9 after
this quake
Strongest of the sequence2.7

How often does it happen here?

about every ~19 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 226 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.

19766.5
Friuli earthquake
6 May 1976 · 42 km from here
IX-XCompletely destructive: most buildings are destroyed.
18736.3
Alpago Cansiglio earthquake
29 June 1873 · 20 km from here
IX-XCompletely destructive: most buildings are destroyed.
19366.1
Alpago Cansiglio earthquake
18 October 1936 · 26 km from here
IXDestructive: many buildings partly or fully collapse.
19286.0
Carnia earthquake
27 March 1928 · 33 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

Andreis-Forgaria nel Friuli

The epicentre lies about 7 km from Andreis-Forgaria nel Friuli, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.7between 1 and 8 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

0.9
11 years ago
10 Aug 2015, 07:14
1.2
11 years ago
10 Aug 2015, 04:30
0.8
11 years ago
7 Aug 2015, 11:46
2.7
3 km South of Erto e Casso
16 km West · 4 km
11 years ago
22 Aug 2015, 14:27
0.4
2 km West of Ampezzo
17 km North-East · 7 km
11 years ago
28 Aug 2015, 08:36
2.3
3 km West of Socchieve
18 km North-East · 6 km
11 years ago
28 Aug 2015, 08:54
1.3
2 km North of Erto e Casso
15 km West · 9 km
11 years ago
2 Sept 2015, 21:31
1.6
4 km South-West of Forni di Sotto
10 km North-East · 6 km
11 years ago
23 Jul 2015, 03:22
2.0
4 km North-West of Chies d'Alpago
16 km South-West · 6 km
11 years ago
6 Sept 2015, 01:41
0.9
3 km East of Frisanco
14 km East · 8 km
11 years ago
7 Sept 2015, 04:26

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).