All earthquakes
1.0
very light
EARTHQUAKE DETAILS

4 km South of Alcara li Fusi

50 months ago · 28 Jul, 07:40

A very light earthquake, probably not felt by people. Being deep, it is felt less at the surface.

Stronger than 30% of Italian events in the past year

Where

4 km South of Alcara li FusiEarthquakes 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

16 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 ≈ 25 s

Animation sped up ~5× compared to reality.

  • Acireale
    55 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Catania
    61 km from the epicentre
    first tremor in ~12 s
    main shaking in ~20 s
  • Messina
    78 km from the epicentre
    first tremor in ~14 s
    main shaking in ~24 s
  • Caltanissetta
    79 km from the epicentre
    first tremor in ~15 s
    main shaking in ~25 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

35 km
deep
4 times the height of Mount Everest

Being deep, it is felt less at the surface.

deeper than the area average (~14 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: 49 months ago the same area had a stronger quake (M2.3). This can only be said after the fact — it was not predictable beforehand.

2.3
The mainshock
5 km South-East of Santo Stefano di Camastra
49 months ago · 11 Aug, 01:30
Activity in the area right now (30 km radius)
0
last 24 hours
5
last 7 days
19
last 30 days
6 before9 after
this quake
Strongest of the sequence2.3

How often does it happen here?

about every ~2 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 2705 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.

17866.1
Golfo di Patti earthquake
10 March 1786 · 34 km from here
IXDestructive: many buildings partly or fully collapse.
18235.8
Sicilia settentrionale earthquake
5 March 1823 · 40 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
16135.6
Monti Nebrodi earthquake
25 August 1613 · 22 km from here
IXDestructive: many buildings partly or fully collapse.
17395.4
Monti Nebrodi earthquake
10 May 1739 · 18 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

Patti-Giardini

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

estimated maximum magnitude 7.1between 3 and 20 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

1.2
3 km North-East of Alcara li Fusi
6 km North-East · 23 km
50 months ago
24 Jul, 17:23
1.6
4 km North of Raccuja
24 km North-East · 17 km
50 months ago
1 Aug, 00:31
0.7
50 months ago
22 Jul, 18:40
1.2
2 km East of Castell'Umberto
19 km North-East · 7 km
50 months ago
3 Aug, 05:46
2.0
4 km North of Adrano
29 km South-East · 17 km
50 months ago
4 Aug, 17:42
1.1
50 months ago
18 Jul, 04:17
1.9
2 km East of San Piero Patti
29 km East · 10 km
49 months ago
9 Aug, 08:11
2.1
2 km South-East of Troina
21 km South · 25 km
49 months ago
9 Aug, 22:39
2.3
49 months ago
11 Aug, 01:30
1.3
49 months ago
11 Aug, 04:15

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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