All earthquakes
1.7
very light
EARTHQUAKE DETAILS

2 km South-West of Francavilla di Sicilia

93 months ago · 31 Oct, 00:36

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 South-West of Francavilla di SiciliaEarthquakes in the province of MessinaEarthquakes in Sicilia

Volcanic area: Mount Etna

Here the ground shakes mostly because of moving magma and underground fluids, not colliding plates: events are typically shallow, frequent and organised in swarms. This activity is constantly monitored by INGV.

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

61 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 ≈ 17 s

Animation sped up ~3× compared to reality.

  • Acireale
    33 km from the epicentre
    first tremor in ~6 s
    main shaking in ~10 s
  • Messina
    47 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Catania
    50 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • Reggio di Calabria
    58 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 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

10 km
medium depth
1.2 times the height of Mount Everest

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

in line with the area average (~15 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?

Seismic swarm

It is part of a seismic swarm: many closely spaced quakes in the same area, with no dominant shock. A typical, well-known behaviour of some Italian areas.

3.2
The mainshock
4 km North-East of Adrano
92 months ago · 20 Nov, 06:06
Activity in the area right now (30 km radius)
11
last 24 hours
19
last 7 days
81
last 30 days
52 before78 after
this quake
Strongest of the sequence3.2

How often does it happen here?

about every ~1 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 2834 events in the last 11 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.

18186.3
Catanese earthquake
20 February 1818 · 36 km from here
IX-XCompletely destructive: most buildings are destroyed.
17866.1
Golfo di Patti earthquake
10 March 1786 · 21 km from here
IXDestructive: many buildings partly or fully collapse.
17495.8
Messina earthquake
August 1749 · 49 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
16135.6
Monti Nebrodi earthquake
25 August 1613 · 35 km from here
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 9 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

1.9
5 km North of Adrano
29 km South-West · 28 km
93 months ago
30 Oct, 15:12
2.4
2 km North of Santa Venerina
25 km South · 9 km
93 months ago
30 Oct, 05:51
2.0
5 km North-West of Sant'Alfio
17 km South-West · 8 km
93 months ago
31 Oct, 19:22
2.0
5 km West of Sant'Alfio
20 km South-West · 4 km
93 months ago
2 Nov, 22:54
2.3
3 km West of Sant'Alfio
20 km South · 9 km
93 months ago
27 Oct, 10:52
1.1
2 km South-East of Falcone
19 km North · 12 km
93 months ago
26 Oct, 13:07
1.2
4 km North-East of Oliveri
25 km North · 9 km
93 months ago
6 Nov, 11:24
1.1
4 km North-East of Oliveri
25 km North · 9 km
93 months ago
6 Nov, 11:27
1.3
4 km North-East of Oliveri
25 km North · 10 km
93 months ago
6 Nov, 11:27
1.3
3 km North of Oliveri
24 km North · 13 km
93 months ago
6 Nov, 11:28

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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