All earthquakes
0.8
very light
EARTHQUAKE DETAILS

M0.8 earthquake · 2 km East of Pianopoli (CZ)

8 years ago · 22 Sept 2018, 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 17% of Italian events in the past year

Where

2 km East of PianopoliEarthquakes in the province of CatanzaroEarthquakes 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.

0.2kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×1,995 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 ≈ 18 s

Animation sped up ~3× compared to reality.

  • Lamezia Terme
    12 km from the epicentre
    first tremor in ~2 s
    main shaking in ~4 s
  • Catanzaro
    17 km from the epicentre
    first tremor in ~3 s
    main shaking in ~5 s
  • Cosenza
    40 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Crotone
    61 km from the epicentre
    first tremor in ~10 s
    main shaking in ~18 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

9 km
shallow

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

shallower than the area average (~16 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: 8 years ago the same area had a stronger quake (M2.4). This can only be said after the fact — it was not predictable beforehand.

2.4
The mainshock
1 km North of Squillace
8 years ago · 24 Sept 2018, 11:05
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
28
last 30 days
2 before7 after
this quake
Strongest of the sequence2.4

How often does it happen here?

about every ~9 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 501 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 · 17 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17837.0
Calabria centrale earthquake
28 March 1783 · 17 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
19057.0
Calabria centrale earthquake
8 September 1905 · 39 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17836.7
Calabria centrale earthquake
7 February 1783 · 44 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.

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

The closest seismic structure

Caraffa-Squillace Gulf

The epicentre lies about 5 km from Caraffa-Squillace Gulf, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.9between 3 and 20 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

1.6
5 km North of San Pietro a Maida
10 km South-West · 38 km
8 years ago
22 Sept 2018, 15:55
1.1
4 km East of Lamezia Terme
8 km West · 11 km
8 years ago
23 Sept 2018, 07:02
2.4
1 km North of Squillace
18 km South-East · 36 km
8 years ago
24 Sept 2018, 11:05
1.4
1 km North of Squillace
18 km South-East · 38 km
8 years ago
24 Sept 2018, 11:31
1.1
4 km East of Parenti
25 km North · 10 km
8 years ago
28 Sept 2018, 19:19
0.6
3 km East of Parenti
25 km North · 9 km
8 years ago
29 Sept 2018, 21:11
1.2
1 km North-West of Grimaldi
29 km North-West · 8 km
8 years ago
11 Sept 2018, 10:36
1.8
1 km West of Taverna
24 km North-East · 6 km
8 years ago
8 Oct 2018, 00:53
1.1
4 km South-West of San Floro
14 km South-East · 11 km
8 years ago
29 Aug 2018, 19:23

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).