All earthquakes
1.6
very light
EARTHQUAKE DETAILS

5 km North of Villarosa

130 months ago · 4 Jan, 15:01

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 74% of Italian events in the past year

Where

5 km North of VillarosaEarthquakes in the province of EnnaEarthquakes in Sicilia

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

13 events
Magnitude:lightweakmoderatestrong

The energy released

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

3.8kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×126 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 ≈ 22 s

Animation sped up ~4× compared to reality.

  • Caltanissetta
    22 km from the epicentre
    first tremor in ~4 s
    main shaking in ~7 s
  • Gela
    60 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • Agrigento
    62 km from the epicentre
    first tremor in ~10 s
    main shaking in ~18 s
  • Bagheria
    76 km from the epicentre
    first tremor in ~13 s
    main shaking in ~22 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.

shallower than the area average (~20 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: 129 months ago the same area had a stronger quake (M2.9). This can only be said after the fact — it was not predictable beforehand.

2.9
The mainshock
7 km West of Resuttano
129 months ago · 21 Jan, 14:47
Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
2
last 30 days
1 before11 after
this quake
Strongest of the sequence2.9

How often does it happen here?

about every ~9 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 485 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.

18195.4
Monti Madonie earthquake
24 February 1819 · 36 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
18185.3
Monti Madonie earthquake
8 September 1818 · 21 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19675.3
Monti Nebrodi earthquake
31 October 1967 · 34 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
17185.3
Sicilia orientale earthquake
20 February 1718 · 41 km from here
VI-VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.

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

The closest seismic structure

Gela-Catania

The epicentre lies about 41 km from Gela-Catania, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.1between 3 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

1.6
9 km South-East of Isnello
25 km North-West · 8 km
129 months ago
16 Jan, 17:41
1.8
6 km North-West of Resuttano
15 km North-West · 37 km
129 months ago
21 Jan, 14:45
2.9
7 km West of Resuttano
17 km West · 35 km
129 months ago
21 Jan, 14:47
1.4
7 km West of Resuttano
16 km West · 35 km
129 months ago
21 Jan, 15:08
1.4
9 km North-West of Resuttano
19 km West · 37 km
129 months ago
22 Jan, 04:16
2.5
9 km West of Resuttano
19 km West · 35 km
129 months ago
22 Jan, 10:33
2.1
129 months ago
23 Jan, 01:18
2.2
3 km East of Valledolmo
30 km West · 36 km
129 months ago
23 Jan, 01:47
2.7
129 months ago
23 Jan, 01:49
2.2
129 months ago
23 Jan, 01:51

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).

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