All earthquakes
1.5
very light
EARTHQUAKE DETAILS

7 km North-West of Troina

73 months ago · 6 Sept, 00:01

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

Stronger than 68% of Italian events in the past year

Where

7 km North-West of TroinaEarthquakes 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

24 events
Magnitude:lightweakmoderatestrong

The energy released

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

2.7kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×178 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 ≈ 27 s

Animation sped up ~5× compared to reality.

  • Acireale
    52 km from the epicentre
    first tremor in ~11 s
    main shaking in ~18 s
  • Catania
    53 km from the epicentre
    first tremor in ~11 s
    main shaking in ~18 s
  • Caltanissetta
    68 km from the epicentre
    first tremor in ~13 s
    main shaking in ~22 s
  • Gela
    86 km from the epicentre
    first tremor in ~15 s
    main shaking in ~27 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: 72 months ago the same area had a stronger quake (M3.1). This can only be said after the fact — it was not predictable beforehand.

3.1
The mainshock
3 km South of Randazzo
72 months ago · 29 Sept, 07:30
Activity in the area right now (30 km radius)
0
last 24 hours
2
last 7 days
12
last 30 days
8 before15 after
this quake
Strongest of the sequence3.1

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: 2501 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 · 46 km from here
IXDestructive: many buildings partly or fully collapse.
18235.8
Sicilia settentrionale earthquake
5 March 1823 · 47 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
16135.6
Monti Nebrodi earthquake
25 August 1613 · 36 km from here
IXDestructive: many buildings partly or fully collapse.
17395.4
Monti Nebrodi earthquake
10 May 1739 · 32 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

Gela-Catania

The epicentre lies about 38 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

0.9
6 km East of San Teodoro
11 km East · 33 km
73 months ago
6 Sept, 05:07
1.6
3 km North-East of Cerami
9 km West · 34 km
73 months ago
4 Sept, 16:43
1.8
8 km West of Adrano
18 km South-East · 7 km
73 months ago
7 Sept, 10:51
1.3
3 km North-East of Adrano
26 km South-East · 9 km
73 months ago
3 Sept, 21:53
1.9
3 km South of Maletto
25 km East · 27 km
73 months ago
10 Sept, 22:24
2.2
3 km East of Mistretta
21 km West · 7 km
73 months ago
27 Aug, 16:46
1.6
7 km North of Ragalna
30 km East · 18 km
72 months ago
17 Sept, 12:07
1.7
5 km East of Nicosia
21 km West · 34 km
73 months ago
23 Aug, 03:25
2.2
7 km South-East of Maletto
29 km East · 28 km
72 months ago
20 Sept, 08:41
1.9
4 km East of Adrano
28 km South-East · 8 km
72 months ago
23 Sept, 15:35

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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