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2.4
light
EARTHQUAKE DETAILS

M2.4 earthquake · 5 km South-East of Grisolia (CS)

8 years ago · 7 Jul 2018, 14:16

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

Stronger than 94% of Italian events in the past year

Where

5 km South-East of GrisoliaEarthquakes in the province of CosenzaEarthquakes 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

16 events
Magnitude:lightweakmoderatestrong

The energy released

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

60kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×7.9 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 ≈ 41 s

Animation sped up ~8× compared to reality.

  • Corigliano-Rossano
    43 km from the epicentre
    first tremor in ~18 s
    main shaking in ~30 s
  • Cosenza
    55 km from the epicentre
    first tremor in ~19 s
    main shaking in ~32 s
  • Lamezia Terme
    88 km from the epicentre
    first tremor in ~22 s
    main shaking in ~37 s
  • Catanzaro
    106 km from the epicentre
    first tremor in ~24 s
    main shaking in ~41 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

97 km
deep
11 times the height of Mount Everest

Being deep, it is felt less at the surface.

deeper than the area average (~28 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?

Mainshock

It is the strongest quake of its sequence: so far it has been followed by 7 aftershocks within 30 km. Aftershocks tend to fade in number and strength over time.

Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
9
last 30 days
8 before7 after
this quake
Strongest of the sequence2.2

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: 458 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.

11846.8
Valle del Crati earthquake
24 May 1184 · 40 km from here
IXDestructive: many buildings partly or fully collapse.
17675.9
Valle del Crati earthquake
14 July 1767 · 46 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
19135.6
Calabria settentrionale earthquake
28 June 1913 · 31 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
18865.6
Cosentino earthquake
6 March 1886 · 46 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.

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

The closest seismic structure

Rimendiello-Mormanno

The epicentre lies about 16 km from Rimendiello-Mormanno, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.6between 1 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

1.7
4 km North-East of Morano Calabro
26 km North-East · 9 km
8 years ago
8 Jul 2018, 20:43
1.3
6 km East of Firmo
26 km East · 9 km
8 years ago
4 Jul 2018, 19:18
0.7
7 km East of Firmo
27 km East · 9 km
8 years ago
4 Jul 2018, 18:15
0.9
7 km South-West of Morano Calabro
16 km North-East · 7 km
8 years ago
2 Jul 2018, 16:18
1.4
3 km North-East of Morano Calabro
25 km North-East · 9 km
8 years ago
15 Jul 2018, 14:03
2.0
6 km East of Firmo
26 km East · 7 km
8 years ago
29 Jun 2018, 11:37
1.5
8 years ago
29 Jun 2018, 11:11
2.2
6 km East of Firmo
26 km East · 7 km
8 years ago
29 Jun 2018, 06:09
1.5
8 years ago
28 Jun 2018, 04:40
1.6
2 km West of Grisolia
7 km West · 23 km
8 years ago
23 Jul 2018, 05:42

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).