All earthquakes
1.8
very light
EARTHQUAKE DETAILS

M1.8 earthquake · 1 km East of Soverzene (BL)

7 years ago · 20 Nov 2018, 19:17

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 82% of Italian events in the past year

Where

1 km East of SoverzeneEarthquakes in the province of BellunoEarthquakes in Veneto

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

5 events
Magnitude:lightweakmoderatestrong

The energy released

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

7.6kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×63 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 ≈ 23 s

Animation sped up ~4× compared to reality.

  • Pordenone
    38 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Treviso
    60 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • Udine
    72 km from the epicentre
    first tremor in ~12 s
    main shaking in ~21 s
  • Bolzano
    81 km from the epicentre
    first tremor in ~14 s
    main shaking in ~23 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: 7 years ago the same area had a stronger quake (M1.9). This can only be said after the fact — it was not predictable beforehand.

1.9
The mainshock
3 km South-West of Longarone
7 years ago · 25 Nov 2018, 10:56
Activity in the area right now (30 km radius)
0
last 24 hours
2
last 7 days
2
last 30 days
1 before3 after
this quake
Strongest of the sequence1.9

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: 184 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.

18736.3
Alpago Cansiglio earthquake
29 June 1873 · 6 km from here
IX-XCompletely destructive: most buildings are destroyed.
19366.1
Alpago Cansiglio earthquake
18 October 1936 · 13 km from here
IXDestructive: many buildings partly or fully collapse.
17946.0
Prealpi Friulane earthquake
7 June 1794 · 39 km from here
IXDestructive: many buildings partly or fully collapse.
17765.8
Prealpi Friulane earthquake
10 July 1776 · 29 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

Bassano-Vittorio Veneto

The epicentre lies about 11 km from Bassano-Vittorio Veneto, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.9between 1 and 10 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
7 years ago
25 Nov 2018, 10:56
1.1
7 km East of Claut
24 km East · 9 km
7 years ago
26 Oct 2018, 15:57
1.8
1 km West of Andreis
21 km East · 10 km
7 years ago
18 Dec 2018, 02:09
1.6
7 years ago
18 Dec 2018, 16:40

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).