All earthquakes
1.0
very light
EARTHQUAKE DETAILS

M1.0 earthquake outside Italy

6 years ago · 20 Aug 2020, 01:35

A very light earthquake, probably not felt by people. At this depth the shaking is felt, but rarely causes damage.

Where

Nearest Italian town: Resia (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?

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

17 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.5kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×1,000 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 ≈ 35 s

Animation sped up ~7× compared to reality.

  • Udine
    36 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Trieste
    79 km from the epicentre
    first tremor in ~13 s
    main shaking in ~23 s
  • Pordenone
    79 km from the epicentre
    first tremor in ~13 s
    main shaking in ~23 s
  • Treviso
    123 km from the epicentre
    first tremor in ~21 s
    main shaking in ~35 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 (~10 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 (M3.0, 6 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

3.0
The mainshock
12 km North of Drenchia
6 years ago · 2 Aug 2020, 18:04
Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
6
last 30 days
11 before5 after
this quake
Strongest of the sequence3.0

How often does it happen here?

about every ~23 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 191 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.
19766.5
Friuli earthquake
6 May 1976 · 32 km from here
IX-XCompletely destructive: most buildings are destroyed.
15116.3
Friuli-Slovenia earthquake
26 March 1511 · 27 km from here
IXDestructive: many buildings partly or fully collapse.
16906.2
Carinthia, Villach earthquake
4 December 1690 · 44 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

Stol

The epicentre lies about 3 km from Stol, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.1between 1 and 7 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

2.8
9 km North of Savogna
7 km South-East · 9 km
6 years ago
21 Aug 2020, 17:49
1.6
6 years ago
14 Aug 2020, 14:39
1.8
13 km North of Pulfero
2 km South · 11 km
6 years ago
13 Aug 2020, 10:32
1.4
13 km East of Resia
1 km South · 10 km
6 years ago
10 Aug 2020, 21:15
0.7
13 km North of Pulfero
2 km South-West · 11 km
6 years ago
9 Aug 2020, 03:19
2.1
6 years ago
8 Aug 2020, 09:38
1.9
13 km East of Resia
1 km South-West · 10 km
6 years ago
8 Aug 2020, 06:50
1.4
6 years ago
1 Sept 2020, 01:27
1.6
6 years ago
1 Sept 2020, 05:25
1.9
14 km East of Resia
1 km South · 11 km
6 years ago
7 Aug 2020, 21:30

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).