All earthquakes
1.9
very light
EARTHQUAKE DETAILS

4 km North of San Giovanni in Fiore

87 months ago · 9 Jul, 11:07

A very light earthquake, probably not felt by people. At this depth the shaking is felt, but rarely causes damage.

Stronger than 85% of Italian events in the past year

Where

4 km North of San Giovanni in FioreEarthquakes 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

15 events
Magnitude:lightweakmoderatestrong

The energy released

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

11kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×45 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 ≈ 14 s

Animation sped up ~3× compared to reality.

  • Cosenza
    31 km from the epicentre
    first tremor in ~6 s
    main shaking in ~10 s
  • Corigliano-Rossano
    39 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Crotone
    46 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Catanzaro
    46 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 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

13 km
medium depth
1.4 times the height of Mount Everest

At this depth the shaking is felt, but rarely causes damage.

in line with the area average (~17 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: 87 months ago the same area had a stronger quake (M2.2). This can only be said after the fact — it was not predictable beforehand.

2.2
The mainshock
3 km East of Pietrafitta
87 months ago · 13 Jul, 00:34
Activity in the area right now (30 km radius)
1
last 24 hours
5
last 7 days
25
last 30 days
8 before6 after
this quake
Strongest of the sequence2.2

How often does it happen here?

about every ~6 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 728 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.

16387.1
Calabria centrale earthquake
27 March 1638 · 41 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
16386.8
Crotonese earthquake
8 June 1638 · 16 km from here
XCompletely destructive: most buildings are destroyed.
11846.8
Valle del Crati earthquake
24 May 1184 · 39 km from here
IXDestructive: many buildings partly or fully collapse.
18326.7
Crotonese earthquake
8 March 1832 · 36 km from here
XCompletely destructive: most buildings are destroyed.

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

The closest seismic structure

Cecita Lake

The epicentre lies about 4 km from Cecita Lake, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.1between 1 and 15 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 Panettieri
26 km South-West · 9 km
87 months ago
11 Jul, 06:16
2.2
3 km East of Pietrafitta
22 km West · 11 km
87 months ago
13 Jul, 00:34
1.3
3 km North-West of Caccuri
16 km South-East · 20 km
87 months ago
15 Jul, 22:07
1.2
87 months ago
18 Jul, 08:48
0.9
2 km North-East of Rogliano
22 km South-West · 19 km
87 months ago
30 Jun, 00:22
0.8
5 km South-West of Acri
27 km North-West · 10 km
87 months ago
26 Jun, 01:34
1.9
86 months ago
22 Jul, 23:01
1.8
86 months ago
27 Jul, 02:54
0.6
7 km North-East of Celico
17 km North-West · 12 km
88 months ago
19 Jun, 00:17
1.0
4 km South-East of Taverna
25 km South · 9 km
88 months ago
18 Jun, 05:02

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).

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