All earthquakes
1.7
very light
EARTHQUAKE DETAILS

3 km East of San Godenzo

125 months ago · 23 Feb, 19:16

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 78% of Italian events in the past year

Where

3 km East of San GodenzoEarthquakes in the province of FirenzeEarthquakes in Toscana

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

20 events
Magnitude:lightweakmoderatestrong

The energy released

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

5.4kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×89 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 ≈ 13 s

Animation sped up ~3× compared to reality.

  • Firenze
    37 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Forlì
    45 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Faenza
    46 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Prato
    46 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 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
1.1 times the height of Mount Everest

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

in line with the area average (~12 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 (M2.7, 126 months ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.7
The mainshock
2 km South-West of Galeata
126 months ago · 8 Feb, 12:23
Activity in the area right now (30 km radius)
0
last 24 hours
2
last 7 days
10
last 30 days
14 before5 after
this quake
Strongest of the sequence2.7

How often does it happen here?

about every ~5 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 825 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.

19196.4
Mugello earthquake
29 June 1919 · 16 km from here
XCompletely destructive: most buildings are destroyed.
17816.1
Faentino earthquake
4 April 1781 · 39 km from here
IX-XCompletely destructive: most buildings are destroyed.
16616.0
Appennino forlivese earthquake
22 March 1661 · 21 km from here
XCompletely destructive: most buildings are destroyed.
15426.0
Mugello earthquake
13 June 1542 · 25 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

Mugello-Citta' di Castello-Leonessa

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

estimated maximum magnitude 6.9between 1 and 8 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

1.6
4 km North-West of Tredozio
19 km North · 28 km
125 months ago
23 Feb, 23:03
1.7
3 km East of Marradi
14 km North · 8 km
126 months ago
19 Feb, 23:08
1.0
5 km South of Premilcuore
10 km East · 8 km
126 months ago
19 Feb, 21:35
1.5
126 months ago
15 Feb, 10:40
1.8
126 months ago
15 Feb, 10:33
2.0
1 km South-West of Galeata
21 km East · 27 km
125 months ago
6 Mar, 14:40
1.2
126 months ago
9 Feb, 14:46
2.0
0 km North of Galeata
21 km East · 26 km
126 months ago
8 Feb, 12:51
1.9
1 km North-East of Galeata
22 km East · 23 km
126 months ago
8 Feb, 12:43
1.2
126 months ago
8 Feb, 12:26

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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