All earthquakes
1.3
very light
EARTHQUAKE DETAILS

M1.3 earthquake · 13 km South-West of Motta San Giovanni (RC)

5 years ago · 15 Dec 2020, 18:17

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

13 km South-West of Motta San GiovanniEarthquakes 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

18 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 ≈ 20 s

Animation sped up ~4× compared to reality.

  • Reggio di Calabria
    22 km from the epicentre
    first tremor in ~4 s
    main shaking in ~7 s
  • Messina
    30 km from the epicentre
    first tremor in ~5 s
    main shaking in ~9 s
  • Acireale
    50 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Catania
    70 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

6 km
shallow

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

shallower than the area average (~15 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 (M2.5, 5 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.5
The mainshock
12 km South-West of Melito di Porto Salvo
5 years ago · 19 Nov 2020, 10:02
Activity in the area right now (30 km radius)
0
last 24 hours
2
last 7 days
9
last 30 days
10 before7 after
this quake
Strongest of the sequence2.5

How often does it happen here?

about every ~4 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 1195 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 · 25 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
18946.1
Calabria meridionale earthquake
16 November 1894 · 47 km from here
IXDestructive: many buildings partly or fully collapse.
19076.0
Aspromonte earthquake
23 October 1907 · 39 km from here
IXDestructive: many buildings partly or fully collapse.
17495.8
Messina earthquake
August 1749 · 28 km from here
VIII-IXDestructive: many buildings partly or fully collapse.

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

The closest seismic structure

Aspromonte-Peloritani

The epicentre sits above this source area: the deep structure where this area's earthquakes can originate.

estimated maximum magnitude 7.3between 2 and 13 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

1.4
5 years ago
15 Dec 2020, 17:57
1.2
3 km South of Reggio di Calabria
20 km North-East · 15 km
5 years ago
16 Dec 2020, 19:51
1.2
5 years ago
18 Dec 2020, 07:29
1.6
5 years ago
19 Dec 2020, 22:50
1.2
3 km South of Reggio di Calabria
20 km North-East · 12 km
5 years ago
22 Dec 2020, 19:32
1.3
5 years ago
23 Dec 2020, 17:46
0.8
5 years ago
5 Dec 2020, 00:39
1.3
5 years ago
1 Dec 2020, 06:04
1.5
2 km South of Calanna
30 km North-East · 10 km
5 years ago
4 Jan 2021, 06:07
1.5
5 years ago
7 Jan 2021, 09:24

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).