All earthquakes
0.9
very light
EARTHQUAKE DETAILS

5 km South-West of San Mauro Castelverde

133 months ago · 16 Sept, 01:51

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 23% of Italian events in the past year

Where

5 km South-West of San Mauro CastelverdeEarthquakes in the province of PalermoEarthquakes 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

11 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.3kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×1,413 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 ≈ 24 s

Animation sped up ~4× compared to reality.

  • Caltanissetta
    49 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Bagheria
    64 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Palermo
    80 km from the epicentre
    first tremor in ~13 s
    main shaking in ~23 s
  • Agrigento
    83 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

9 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?

Aftershock

It is an aftershock: it follows a stronger quake (M2.5, 134 months ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.5
The mainshock
2 km North-West of Pettineo
134 months ago · 18 Aug, 05:13
Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
14
last 30 days
8 before2 after
this quake
Strongest of the sequence2.5

How often does it happen here?

about every ~7 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 618 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 · 35 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
18195.4
Monti Madonie earthquake
24 February 1819 · 14 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
18185.3
Monti Madonie earthquake
8 September 1818 · 13 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19675.3
Monti Nebrodi earthquake
31 October 1967 · 20 km from here
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 54 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

1.0
7 km South-East of Isnello
11 km West · 6 km
133 months ago
16 Sept, 01:29
1.4
4 km South-East of Pollina
9 km North-West · 4 km
134 months ago
8 Sept, 08:41
1.4
6 km West of San Mauro Castelverde
4 km North-West · 28 km
134 months ago
7 Sept, 20:13
1.9
6 km South-East of Scillato
20 km West · 17 km
133 months ago
24 Sept, 10:48
1.7
4 km South-East of Pollina
9 km North-West · 4 km
134 months ago
7 Sept, 04:47
1.0
134 months ago
6 Sept, 18:57
1.7
1 km East of Calascibetta
29 km South · 9 km
134 months ago
4 Sept, 10:57
1.8
133 months ago
3 Oct, 22:36
1.2
3 km South-West of Petralia Soprana
16 km South-West · 35 km
134 months ago
27 Aug, 02:09
2.5
2 km North-West of Pettineo
10 km North-East · 25 km
134 months ago
18 Aug, 05:13

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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