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2.3
light
EARTHQUAKE DETAILS

M2.3 earthquake · 1 km North-West of Sinopoli (RC)

9 years ago · 22 Sept 2017, 06:42

A light earthquake, rarely felt by people. At only a few km deep the shaking is felt more sharply at the surface.

Stronger than 93% of Italian events in the past year

Where

1 km North-West of SinopoliEarthquakes 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

10 events
Magnitude:lightweakmoderatestrong

The energy released

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

43kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×11 its energy
M1this quakeM3

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 ≈ 27 s

Animation sped up ~5× compared to reality.

  • Reggio di Calabria
    23 km from the epicentre
    first tremor in ~4 s
    main shaking in ~7 s
  • Messina
    33 km from the epicentre
    first tremor in ~6 s
    main shaking in ~10 s
  • Lamezia Terme
    84 km from the epicentre
    first tremor in ~14 s
    main shaking in ~24 s
  • Catanzaro
    93 km from the epicentre
    first tremor in ~16 s
    main shaking in ~27 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
1 times the height of Mount Everest

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

shallower than the area average (~40 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 (M2.6). This can only be said after the fact — it was not predictable beforehand.

2.6
The mainshock
3 km East of Fiumara
8 years ago · 20 Oct 2017, 20:21
Activity in the area right now (30 km radius)
0
last 24 hours
5
last 7 days
15
last 30 days
3 before6 after
this quake
Strongest of the sequence2.6

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: 1163 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 · 22 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17837.1
Calabria meridionale earthquake
5 February 1783 · 8 km from here
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.
18946.1
Calabria meridionale earthquake
16 November 1894 · 3 km from here
IXDestructive: many buildings partly or fully collapse.

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

The closest seismic structure

Gioia Tauro

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

estimated maximum magnitude 7.1between 3 and 11 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

1.2
9 years ago
23 Sept 2017, 03:43
1.8
9 years ago
27 Sept 2017, 01:35
1.5
5 km South-West of Nicotera
28 km North · 11 km
9 years ago
16 Sept 2017, 02:23
2.0
9 years ago
14 Sept 2017, 10:24
2.1
5 km West of Taurianova
12 km North-East · 47 km
9 years ago
2 Oct 2017, 18:48
2.4
9 km North-West of Palmi
20 km North-West · 46 km
9 years ago
2 Sept 2017, 12:32
1.5
2 km West of Molochio
14 km East · 14 km
8 years ago
16 Oct 2017, 09:28
1.3
2 km East of San Roberto
10 km South-West · 7 km
8 years ago
17 Oct 2017, 06:00
2.6
3 km East of Fiumara
15 km West · 10 km
8 years ago
20 Oct 2017, 20:21

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).