All earthquakes
3.7
weak
EARTHQUAKE DETAILS

1 km West of San Nicola dell'Alto

8 months ago · 4 Jan, 18:48

A weak earthquake, felt by some of the population. At this depth the shaking is felt, but rarely causes damage.

No. 6 of the month in ItalyStronger than 99% of Italian events in the past year

Where

1 km West of San Nicola dell'AltoEarthquakes in the province of CrotoneEarthquakes in Calabria

How far away could it be felt?

An estimate of how far people may have felt this quake.

  • up to ~18 km · felt only by some, at rest
    ≈ 60,000 people live in this area

The coloured rings on the map below show these distances.

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

12 events
Magnitude:lightweakmoderatestrong

The energy released

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

5.4tof TNT equivalent
22 lightning bolts
M3
×11 the energy of a magnitude 3 earthquake
M3this quakeM5

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 ≈ 19 s

Animation sped up ~3× compared to reality.

  • Crotone
    22 km from the epicentre
    first tremor in ~6 s
    main shaking in ~10 s
  • Catanzaro
    53 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • Cosenza
    59 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Corigliano-Rossano
    59 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 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

27 km
medium depth
3 times the height of Mount Everest

At this depth the shaking is felt, but rarely causes damage.

deeper than the area average (~19 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?

Mainshock

It is the strongest quake of its sequence: so far it has been followed by 9 aftershocks within 30 km. Aftershocks tend to fade in number and strength over time.

Activity in the area right now (30 km radius)
1
last 24 hours
3
last 7 days
6
last 30 days
2 before9 after
this quake
Strongest of the sequence3.0

How often does it happen here?

about every ~5 months

Within 50 km of this epicentre, a magnitude ≥ 3.5 earthquake has occurred on average this often: 29 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.

16386.8
Crotonese earthquake
8 June 1638 · 13 km from here
XCompletely destructive: most buildings are destroyed.
18326.7
Crotonese earthquake
8 March 1832 · 22 km from here
XCompletely destructive: most buildings are destroyed.
18366.2
Calabria settentrionale earthquake
25 April 1836 · 38 km from here
XCompletely destructive: most buildings are destroyed.
17445.7
Sila Piccola earthquake
21 March 1744 · 30 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

Crotone-Rossano

The epicentre lies about 12 km from Crotone-Rossano, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.3between 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

2.0
8 months ago
4 Jan, 18:52
2.3
8 months ago
4 Jan, 18:53
2.0
8 months ago
5 Jan, 06:09
1.3
8 months ago
4 Jan, 05:49
3.0
3 km South of Pallagorio
4 km West · 23 km
8 months ago
5 Jan, 11:19
2.0
2 km North-West of Casabona
2 km South-West · 11 km
8 months ago
5 Jan, 11:21
2.2
8 months ago
5 Jan, 16:52
1.4
2 km West of Casabona
5 km South-West · 11 km
8 months ago
6 Jan, 03:15
1.2
6 km West of Umbriatico
14 km North-West · 25 km
8 months ago
14 Jan, 02:49
1.7
3 km North-West of Casabona
4 km West · 11 km
7 months ago
16 Jan, 14:35

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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