All earthquakes
1.9
very light
EARTHQUAKE DETAILS

20 km North of Villafranca Tirrena

96 months ago · 31 Jul, 21:55

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

Stronger than 85% of Italian events in the past year

Where

20 km North of Villafranca TirrenaEarthquakes 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

27 events
Magnitude:lightweakmoderatestrong

The energy released

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

11kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×45 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 ≈ 44 s

Animation sped up ~8× compared to reality.

  • Messina
    24 km from the epicentre
    first tremor in ~20 s
    main shaking in ~35 s
  • Reggio di Calabria
    41 km from the epicentre
    first tremor in ~21 s
    main shaking in ~36 s
  • Acireale
    88 km from the epicentre
    first tremor in ~25 s
    main shaking in ~43 s
  • Lamezia Terme
    97 km from the epicentre
    first tremor in ~26 s
    main shaking in ~44 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

120 km
deep
14 times the height of Mount Everest

Being deep, it is felt less at the surface.

deeper than the area average (~47 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 (M3.0, 96 months ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

3.0
The mainshock
23 km North of Milazzo
96 months ago · 31 Jul, 17:20
Activity in the area right now (30 km radius)
1
last 24 hours
26
last 7 days
46
last 30 days
12 before14 after
this quake
Strongest of the sequence3.0

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: 1853 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.

19087.1
Stretto di Messina earthquake
28 December 1908 · 36 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17837.1
Calabria meridionale earthquake
5 February 1783 · 48 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17866.1
Golfo di Patti earthquake
10 March 1786 · 48 km from here
IXDestructive: many buildings partly or fully collapse.
18946.1
Calabria meridionale earthquake
16 November 1894 · 40 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

Bagnara-Bovalino

The epicentre lies about 15 km from Bagnara-Bovalino, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.1between 3 and 12 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

2.1
24 km West of Ricadi
26 km North-East · 89 km
96 months ago
1 Aug, 00:25
3.0
23 km North of Milazzo
17 km West · 182 km
96 months ago
31 Jul, 17:20
1.0
7 km South-East of Messina
30 km South-East · 10 km
96 months ago
1 Aug, 05:17
2.3
24 km North of Villafranca Tirrena
6 km North-East · 130 km
96 months ago
31 Jul, 06:17
1.8
96 months ago
29 Jul, 03:39
2.3
23 km South-East of Lipari
22 km West · 169 km
96 months ago
28 Jul, 01:18
2.3
96 months ago
27 Jul, 23:38
1.1
5 km East of Messina
24 km South-East · 1 km
96 months ago
26 Jul, 08:54
1.9
Tirreno Meridionale [Mare]
15 km North-East · 127 km
96 months ago
7 Aug, 00:42
1.1
3 km North-West of Torregrotta
22 km South-West · 11 km
96 months ago
25 Jul, 07:44

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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