All earthquakes
1.8
very light
EARTHQUAKE DETAILS

19 km North-West of Zambrone

74 months ago · 25 Jul, 04:27

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

19 km North-West of ZambroneEarthquakes in the province of Vibo ValentiaEarthquakes in Calabria

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

18 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 ≈ 23 s

Animation sped up ~4× compared to reality.

  • Lamezia Terme
    36 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Cosenza
    58 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • Catanzaro
    62 km from the epicentre
    first tremor in ~10 s
    main shaking in ~18 s
  • Messina
    80 km from the epicentre
    first tremor in ~13 s
    main shaking in ~23 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

6 km
shallow

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

shallower than the area average (~65 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: 74 months ago the same area had a stronger quake (M2.6). This can only be said after the fact — it was not predictable beforehand.

2.6
The mainshock
23 km West of Tropea
74 months ago · 4 Aug, 12:06
Activity in the area right now (30 km radius)
0
last 24 hours
2
last 7 days
11
last 30 days
9 before8 after
this quake
Strongest of the sequence2.6

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: 870 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.

16387.1
Calabria centrale earthquake
27 March 1638 · 41 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
19057.0
Calabria centrale earthquake
8 September 1905 · 11 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17836.7
Calabria centrale earthquake
7 February 1783 · 41 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
16596.6
Calabria centrale earthquake
5 November 1659 · 36 km from here
XCompletely destructive: most buildings are destroyed.

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

The closest seismic structure

Sant'Eufemia

The epicentre lies about 18 km from Sant'Eufemia, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.1between 1 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

1.4
13 km North-West of Ricadi
22 km South-West · 66 km
74 months ago
25 Jul, 08:48
1.2
18 km North of Tropea
4 km South-West · 6 km
74 months ago
24 Jul, 22:02
1.4
74 months ago
25 Jul, 18:13
1.5
8 km South-West of Amantea
25 km North-East · 23 km
74 months ago
24 Jul, 00:41
1.8
Tirreno Meridionale [Mare]
28 km West · 91 km
74 months ago
21 Jul, 21:13
1.1
8 km South-West of Amantea
26 km North-East · 21 km
74 months ago
21 Jul, 19:09
2.0
Tirreno Meridionale [Mare]
18 km West · 164 km
74 months ago
21 Jul, 13:45
1.3
6 km West of Falerna
25 km North-East · 7 km
74 months ago
20 Jul, 19:10
2.6
23 km West of Tropea
22 km West · 157 km
74 months ago
4 Aug, 12:06

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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