All earthquakes
1.7
very light
EARTHQUAKE DETAILS

2 km North-East of Castel di Lucio

72 months ago · 18 Sept, 12:20

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

Stronger than 78% of Italian events in the past year

Where

2 km North-East of Castel di LucioEarthquakes in the province of MessinaEarthquakes 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

41 events
Magnitude:lightweakmoderatestrong

The energy released

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

5.4kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×89 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 ≈ 24 s

Animation sped up ~4× compared to reality.

  • Caltanissetta
    53 km from the epicentre
    first tremor in ~9 s
    main shaking in ~16 s
  • Bagheria
    73 km from the epicentre
    first tremor in ~13 s
    main shaking in ~21 s
  • Catania
    80 km from the epicentre
    first tremor in ~14 s
    main shaking in ~24 s
  • Acireale
    82 km from the epicentre
    first tremor in ~14 s
    main shaking in ~24 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

18 km
medium depth
2 times the height of Mount Everest

At this depth the shaking is felt, but rarely causes damage.

in line with the area average (~18 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: 71 months ago the same area had a stronger quake (M3.2). This can only be said after the fact — it was not predictable beforehand.

3.2
The mainshock
7 km East of Cerami
71 months ago · 17 Oct, 14:29
Activity in the area right now (30 km radius)
0
last 24 hours
3
last 7 days
19
last 30 days
3 before37 after
this quake
Strongest of the sequence3.2

How often does it happen here?

about every ~5 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 831 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.

18235.8
Sicilia settentrionale earthquake
5 March 1823 · 33 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
17395.4
Monti Nebrodi earthquake
10 May 1739 · 46 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
18195.4
Monti Madonie earthquake
24 February 1819 · 23 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.

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

The closest seismic structure

Southern Tyrrhenian S

The epicentre lies about 55 km from Southern Tyrrhenian S, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.0between 3 and 16 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

1.5
72 months ago
21 Sept, 19:55
1.2
1 km South-West of Pollina
19 km North-West · 4 km
72 months ago
22 Sept, 13:47
1.6
3 km North-East of Cerami
21 km East · 34 km
73 months ago
4 Sept, 16:43
2.2
3 km East of Mistretta
10 km East · 7 km
73 months ago
27 Aug, 16:46
1.7
5 km East of Nicosia
20 km South-East · 34 km
73 months ago
23 Aug, 03:25
1.9
7 km East of Cerami
26 km East · 35 km
71 months ago
17 Oct, 05:19
2.1
7 km East of Cerami
27 km East · 37 km
71 months ago
17 Oct, 05:50
1.7
7 km East of Cerami
26 km East · 37 km
71 months ago
17 Oct, 06:09
2.7
5 km East of Cerami
26 km East · 34 km
71 months ago
17 Oct, 06:27
1.5
8 km East of Cerami
27 km East · 34 km
71 months ago
17 Oct, 07:28

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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