All earthquakes
1.1
very light
EARTHQUAKE DETAILS

M1.1 earthquake · 7 km North-West of Bocchigliero (CS)

5 years ago · 16 Sept 2021, 00:36

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

Stronger than 39% of Italian events in the past year

Where

7 km North-West of BocchiglieroEarthquakes 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

21 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.

  • Corigliano-Rossano
    30 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Cosenza
    41 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • Crotone
    51 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • Catanzaro
    62 km from the epicentre
    first tremor in ~12 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

34 km
deep
3.8 times the height of Mount Everest

Being deep, it is felt less at the surface.

deeper than the area average (~18 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 (M2.9, 5 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.9
The mainshock
4 km South-West of Acri
5 years ago · 3 Sept 2021, 04:11
Activity in the area right now (30 km radius)
0
last 24 hours
3
last 7 days
12
last 30 days
6 before14 after
this quake
Strongest of the sequence2.9

How often does it happen here?

about every ~7 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 614 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 · 21 km from here
XCompletely destructive: most buildings are destroyed.
11846.8
Valle del Crati earthquake
24 May 1184 · 44 km from here
IXDestructive: many buildings partly or fully collapse.
18326.7
Crotonese earthquake
8 March 1832 · 45 km from here
XCompletely destructive: most buildings are destroyed.
18546.3
Cosentino earthquake
12 February 1854 · 41 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

Cecita Lake

The epicentre lies about 13 km from Cecita Lake, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.1between 1 and 15 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

1.5
2 km West of San Giorgio Albanese
28 km North-West · 18 km
5 years ago
21 Sept 2021, 14:07
1.0
6 km South-West of Acri
28 km West · 11 km
5 years ago
8 Sept 2021, 13:24
1.4
3 km West of Spezzano della Sila
26 km South-West · 17 km
5 years ago
25 Sept 2021, 17:19
1.4
2 km West of Acri
25 km West · 10 km
5 years ago
4 Sept 2021, 19:28
2.9
4 km South-West of Acri
26 km West · 10 km
5 years ago
3 Sept 2021, 04:11
0.6
1 km East of San Cosmo Albanese
28 km North-West · 10 km
5 years ago
28 Aug 2021, 00:00
1.1
3 km South-East of Casali del Manco
25 km South-West · 16 km
5 years ago
25 Aug 2021, 15:05
1.4
9 km West of Bocchigliero
11 km South-West · 13 km
5 years ago
23 Aug 2021, 21:50
1.1
5 km East of Luzzi
30 km West · 14 km
5 years ago
9 Oct 2021, 04:02
2.2
4 km East of Rose
29 km West · 12 km
5 years ago
11 Oct 2021, 08:42

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).