All earthquakes
1.5
very light
EARTHQUAKE DETAILS

Costa Siciliana nord-orientale (Messina)

86 months ago · 6 Aug, 11:37

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 68% of Italian events in the past year

Where

Costa Siciliana nord-orientale (Messina)Earthquakes in the province of MessinaEarthquakes in Sicilia

Epicentre at sea

The epicentre is at sea: for the same magnitude, the shaking is felt less on land, because the energy fades along the way before reaching the coast.

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

4 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 ≈ 31 s

Animation sped up ~6× compared to reality.

  • Bagheria
    71 km from the epicentre
    first tremor in ~12 s
    main shaking in ~20 s
  • Palermo
    84 km from the epicentre
    first tremor in ~14 s
    main shaking in ~24 s
  • Caltanissetta
    92 km from the epicentre
    first tremor in ~15 s
    main shaking in ~26 s
  • Acireale
    107 km from the epicentre
    first tremor in ~18 s
    main shaking in ~31 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 (~17 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: 86 months ago the same area had a stronger quake (M1.9). This can only be said after the fact — it was not predictable beforehand.

1.9
The mainshock
2 km North of Motta d'Affermo
86 months ago · 6 Aug, 15:40
Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
9
last 30 days
1 before2 after
this quake
Strongest of the sequence1.9

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: 801 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 · 12 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
19805.7
Tirreno meridionale earthquake
28 May 1980 · 23 km from here
VI-VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.
16135.6
Monti Nebrodi earthquake
25 August 1613 · 49 km from here
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.

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

The closest seismic structure

Southern Tyrrhenian S

The epicentre lies about 13 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

1.9
2 km North of Motta d'Affermo
30 km South · 17 km
86 months ago
6 Aug, 15:40
1.4
86 months ago
5 Aug, 15:15
1.3
86 months ago
16 Aug, 18:26

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).

We use cookies to analyse site traffic and improve your experience.

Privacy PolicyCookie Policy