All earthquakes
1.8
very light
EARTHQUAKE DETAILS

20 km West of Leni

96 months ago · 13 Jul, 04:13

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 82% of Italian events in the past year

Where

20 km West of LeniEarthquakes 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

8 events
Magnitude:lightweakmoderatestrong

The energy released

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

7.6kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×63 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 ≈ 33 s

Animation sped up ~6× compared to reality.

  • Messina
    89 km from the epicentre
    first tremor in ~15 s
    main shaking in ~26 s
  • Reggio di Calabria
    110 km from the epicentre
    first tremor in ~18 s
    main shaking in ~31 s
  • Bagheria
    110 km from the epicentre
    first tremor in ~18 s
    main shaking in ~32 s
  • Acireale
    114 km from the epicentre
    first tremor in ~19 s
    main shaking in ~33 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
1 times the height of Mount Everest

At only a few km deep the shaking is felt more sharply at the surface.

shallower than the area average (~42 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: 96 months ago the same area had a stronger quake (M3.3). This can only be said after the fact — it was not predictable beforehand.

3.3
The mainshock
Isole Eolie (Messina)
96 months ago · 10 Aug, 13:55
Activity in the area right now (30 km radius)
1
last 24 hours
1
last 7 days
11
last 30 days
2 before5 after
this quake
Strongest of the sequence3.3

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: 877 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.

19786.0
Golfo di Patti earthquake
15 April 1978 · 46 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
18235.8
Sicilia settentrionale earthquake
5 March 1823 · 46 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
19805.7
Tirreno meridionale earthquake
28 May 1980 · 30 km from here
VI-VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.
20045.4
Isole Eolie earthquake
5 May 2004 · 17 km from here
IVModerate: felt by many indoors; glasses and dishes rattle.

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

The closest seismic structure

Southern Tyrrhenian

The epicentre sits above this source area: the deep structure where this area's earthquakes can originate.

estimated maximum magnitude 8.2between 2 and 18 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

2.5
25 km South-West of Leni
21 km South-East · 207 km
97 months ago
8 Jul, 21:39
2.4
Tirreno Meridionale [Mare]
25 km North · 273 km
97 months ago
5 Jul, 00:33
3.1
Isole Eolie (Messina)
24 km West · 20 km
96 months ago
4 Aug, 08:40
1.8
96 months ago
4 Aug, 19:15
1.8
Isole Eolie (Messina)
26 km West · 15 km
96 months ago
9 Aug, 08:46
3.3
Isole Eolie (Messina)
25 km West · 21 km
96 months ago
10 Aug, 13:55
2.0
Isole Eolie (Messina)
26 km West · 23 km
95 months ago
11 Aug, 10:59

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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