All earthquakes
1.8
very light
EARTHQUAKE DETAILS

M1.8 earthquake · 1 km East of Posina (VI)

3 years ago · 22 Jul 2023, 15:12

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 PosinaEarthquakes in the province of VicenzaEarthquakes 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

12 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 ≈ 19 s

Animation sped up ~3× compared to reality.

  • Trento
    30 km from the epicentre
    first tremor in ~5 s
    main shaking in ~9 s
  • Vicenza
    35 km from the epicentre
    first tremor in ~6 s
    main shaking in ~10 s
  • Verona
    45 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Padova
    65 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 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

7 km
shallow

At only a few km deep the shaking is felt more sharply at the surface.

in line with the area average (~6 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: 3 years ago the same area had a stronger quake (M2.0). This can only be said after the fact — it was not predictable beforehand.

2.0
The mainshock
5 km East of Brentonico
3 years ago · 6 Aug 2023, 23:57
Activity in the area right now (30 km radius)
0
last 24 hours
2
last 7 days
5
last 30 days
3 before8 after
this quake
Strongest of the sequence2.0

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.

16956.4
Asolano earthquake
25 February 1695 · 50 km from here
XCompletely destructive: most buildings are destroyed.
18915.9
Valle d'Illasi earthquake
7 June 1891 · 28 km from here
IXDestructive: many buildings partly or fully collapse.
18365.5
Asolano earthquake
12 June 1836 · 43 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19325.2
Garda orientale earthquake
19 February 1932 · 46 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.

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

The closest seismic structure

Schio-Vicenza

The epicentre sits above this source area: the deep structure where this area's earthquakes can originate.

estimated maximum magnitude 7.3between 1 and 15 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

1.1
3 km South-West of Mori
27 km West · 16 km
3 years ago
12 Jul 2023, 15:25
0.7
4 km North-East of Ala
17 km West · 9 km
3 years ago
3 Aug 2023, 14:53
2.0
5 km East of Brentonico
21 km West · 11 km
3 years ago
6 Aug 2023, 23:57
1.1
3 years ago
6 Jul 2023, 23:00
0.9
0 km South-West of Pedemonte
13 km North · 16 km
3 years ago
5 Jul 2023, 06:24
0.8
3 km South-West of Ala
22 km West · 8 km
3 years ago
10 Aug 2023, 01:59
1.2
6 km South of Rovereto
19 km West · 13 km
3 years ago
11 Aug 2023, 14:47
1.0
3 km South-West of Vallarsa
15 km West · 11 km
3 years ago
12 Aug 2023, 03:00
1.6
3 years ago
14 Aug 2023, 19:54
1.3
3 years ago
14 Aug 2023, 19:56

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).