All earthquakes
1.3
very light
EARTHQUAKE DETAILS

M1.3 earthquake · 5 km North-West of San Ferdinando (RC)

8 years ago · 21 Nov 2017, 16:12

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 55% of Italian events in the past year

Where

5 km North-West of San FerdinandoEarthquakes in the province of Reggio CalabriaEarthquakes 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

9 events
Magnitude:lightweakmoderatestrong

The energy released

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

1.3kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×355 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 ≈ 22 s

Animation sped up ~4× compared to reality.

  • Reggio di Calabria
    47 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Messina
    48 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Lamezia Terme
    61 km from the epicentre
    first tremor in ~10 s
    main shaking in ~18 s
  • Catanzaro
    75 km from the epicentre
    first tremor in ~13 s
    main shaking in ~22 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 (~54 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, 8 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.3
The mainshock
11 km North-West of Tropea
8 years ago · 7 Nov 2017, 09:03
Activity in the area right now (30 km radius)
0
last 24 hours
3
last 7 days
8
last 30 days
4 before4 after
this quake
Strongest of the sequence2.3

How often does it happen here?

about every ~3 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 1431 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.

19087.1
Stretto di Messina earthquake
28 December 1908 · 44 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17837.1
Calabria meridionale earthquake
5 February 1783 · 24 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
19057.0
Calabria centrale earthquake
8 September 1905 · 36 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17836.7
Calabria centrale earthquake
7 February 1783 · 28 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

Nicotera-Roccella Ionica

The epicentre lies about 3 km from Nicotera-Roccella Ionica, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.9between 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

0.8
2 km South-West of Cittanova
22 km South-East · 18 km
8 years ago
21 Nov 2017, 12:46
2.3
11 km North-West of Tropea
30 km North · 58 km
8 years ago
7 Nov 2017, 09:03
0.9
2 km South-East of Rosarno
11 km East · 10 km
8 years ago
7 Dec 2017, 04:16
1.3
10 km North-West of Palmi
12 km South-West · 39 km
8 years ago
8 Dec 2017, 02:04
1.8
11 km North-West of Palmi
11 km South-West · 44 km
8 years ago
11 Dec 2017, 21:55
2.0
22 km South-West of Ricadi
20 km West · 49 km
8 years ago
27 Oct 2017, 14:27
2.1
10 km North-West of Tropea
28 km North · 53 km
8 years ago
25 Oct 2017, 05:08
1.9
Tirreno Meridionale [Mare]
25 km West · 136 km
8 years ago
19 Dec 2017, 23:19

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).