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2.1
light
EARTHQUAKE DETAILS

M2.1 earthquake · 7 km West of Joppolo (VV)

8 years ago · 14 Sept 2018, 04:36

A light earthquake, rarely felt by people. Being deep, it is felt less at the surface.

Stronger than 90% of Italian events in the past year

Where

7 km West of JoppoloEarthquakes in the province of Vibo ValentiaEarthquakes 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

61 events
Magnitude:lightweakmoderatestrong

The energy released

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

21kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×22 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.

  • Messina
    50 km from the epicentre
    first tremor in ~12 s
    main shaking in ~21 s
  • Reggio di Calabria
    53 km from the epicentre
    first tremor in ~13 s
    main shaking in ~22 s
  • Lamezia Terme
    59 km from the epicentre
    first tremor in ~14 s
    main shaking in ~23 s
  • Catanzaro
    76 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

55 km
deep
6.2 times the height of Mount Everest

Being deep, it is felt less at the surface.

shallower than the area average (~65 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 (M4.0). This can only be said after the fact — it was not predictable beforehand.

4.0
The mainshock
13 km West of Palmi
8 years ago · 28 Sept 2018, 07:24
Activity in the area right now (30 km radius)
0
last 24 hours
3
last 7 days
8
last 30 days
9 before93 after
this quake
Strongest of the sequence4.0

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: 1613 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 · 49 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17837.1
Calabria meridionale earthquake
5 February 1783 · 34 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
19057.0
Calabria centrale earthquake
8 September 1905 · 31 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17836.7
Calabria centrale earthquake
7 February 1783 · 33 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 11 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

1.3
2 km East of Rizziconi
24 km South-East · 9 km
8 years ago
16 Sept 2018, 06:28
1.8
Tirreno Meridionale [Mare]
29 km West · 133 km
8 years ago
18 Sept 2018, 02:56
1.6
Tirreno Meridionale [Mare]
27 km West · 92 km
8 years ago
19 Sept 2018, 10:30
2.2
Tirreno Meridionale [Mare]
30 km West · 134 km
8 years ago
20 Sept 2018, 01:36
1.9
Tirreno Meridionale [Mare]
30 km West · 130 km
8 years ago
20 Sept 2018, 02:56
2.3
22 km West of Ricadi
23 km North-West · 162 km
8 years ago
7 Sept 2018, 11:54
0.6
5 km South-West of Rizziconi
25 km South-East · 10 km
8 years ago
21 Sept 2018, 19:52
2.9
Tirreno Meridionale [Mare]
24 km West · 160 km
8 years ago
23 Sept 2018, 04:27
1.9
24 km North-West of Ricadi
25 km North-West · 161 km
8 years ago
23 Sept 2018, 16:05
1.0
12 km West of Palmi
23 km South · 11 km
8 years ago
25 Sept 2018, 06:36

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).