All earthquakes
1.1
very light
EARTHQUAKE DETAILS

M1.1 earthquake · 13 km West of Longobardi (CS)

4 years ago · 30 Dec 2021, 23:56

A very light earthquake, probably not felt by people. At this depth the shaking is felt, but rarely causes damage.

Stronger than 39% of Italian events in the past year

Where

13 km West of LongobardiEarthquakes in the province of CosenzaEarthquakes 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

10 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.7kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×708 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 ≈ 20 s

Animation sped up ~4× compared to reality.

  • Cosenza
    30 km from the epicentre
    first tremor in ~5 s
    main shaking in ~9 s
  • Lamezia Terme
    41 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Corigliano-Rossano
    63 km from the epicentre
    first tremor in ~11 s
    main shaking in ~18 s
  • Catanzaro
    67 km from the epicentre
    first tremor in ~11 s
    main shaking in ~20 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

10 km
medium depth
1.2 times the height of Mount Everest

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

shallower than the area average (~48 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 (M2.3, 4 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.3
The mainshock
21 km West of Paola
4 years ago · 13 Dec 2021, 03:29
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
4
last 30 days
7 before2 after
this quake
Strongest of the sequence2.3

How often does it happen here?

about every ~6 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 721 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 · 35 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
19057.0
Calabria centrale earthquake
8 September 1905 · 45 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
11846.8
Valle del Crati earthquake
24 May 1184 · 30 km from here
IXDestructive: many buildings partly or fully collapse.
18546.3
Cosentino earthquake
12 February 1854 · 31 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

Savuto Valley

The epicentre lies about 26 km from Savuto Valley, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.1between 2 and 14 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

1.3
4 km West of Falerna
29 km South-East · 23 km
4 years ago
29 Dec 2021, 22:39
1.5
6 km West of Longobardi
8 km East · 46 km
4 years ago
25 Dec 2021, 06:37
1.7
2 km North-West of Lago
18 km East · 28 km
4 years ago
15 Dec 2021, 17:18
2.0
3 km South of Castrolibero
26 km East · 56 km
4 years ago
15 Dec 2021, 04:41
2.3
21 km West of Paola
17 km North-West · 120 km
4 years ago
13 Dec 2021, 03:29
1.2
2 km West of Malito
26 km East · 8 km
4 years ago
18 Jan 2022, 12:19
2.2
Costa Calabra nord-occidentale (Cosenza)
14 km West · 59 km
4 years ago
11 Dec 2021, 01:53
0.8
4 km West of Cosenza
27 km East · 9 km
4 years ago
20 Jan 2022, 04:46
2.0
7 km West of Fuscaldo
24 km North · 54 km
4 years ago
6 Dec 2021, 05:00

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).