All earthquakes
0.5
very light
EARTHQUAKE DETAILS

5 km East of Vernio

49 months ago · 10 Aug, 11:54

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 3% of Italian events in the past year

Where

5 km East of VernioEarthquakes in the province of PratoEarthquakes 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

40 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.1kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×5,623 its energy
M0this quakeM2

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 ~2× compared to reality.

  • Prato
    25 km from the epicentre
    first tremor in ~4 s
    main shaking in ~7 s
  • Pistoia
    27 km from the epicentre
    first tremor in ~5 s
    main shaking in ~8 s
  • Firenze
    35 km from the epicentre
    first tremor in ~6 s
    main shaking in ~10 s
  • Bologna
    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

4 km
shallow

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

shallower than the area average (~13 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 (M2.1, 50 months ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.1
The mainshock
6 km South-East of Montese
50 months ago · 23 Jul, 09:00
Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
19
last 30 days
23 before16 after
this quake
Strongest of the sequence2.1

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: 981 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 · 26 km from here
XCompletely destructive: most buildings are destroyed.
17816.1
Faentino earthquake
4 April 1781 · 50 km from here
IX-XCompletely destructive: most buildings are destroyed.
15426.0
Mugello earthquake
13 June 1542 · 17 km from here
IXDestructive: many buildings partly or fully collapse.
17255.7
Appennino tosco-emiliano earthquake
29 October 1725 · 32 km from here
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

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

1.7
1 km South of Grizzana Morandi
18 km North-West · 19 km
49 months ago
10 Aug, 20:38
1.7
0 km South-West of Grizzana Morandi
19 km North-West · 19 km
49 months ago
10 Aug, 20:39
1.5
1 km South-West of Grizzana Morandi
18 km North-West · 19 km
49 months ago
10 Aug, 20:41
1.4
3 km West of Gaggio Montano
26 km North-West · 10 km
49 months ago
7 Aug, 06:37
1.1
49 months ago
13 Aug, 17:41
1.6
5 km West of Castel del Rio
22 km North-East · 11 km
49 months ago
7 Aug, 00:10
0.8
5 km North-East of Pistoia
24 km West · 10 km
49 months ago
6 Aug, 23:34
1.3
5 km North-East of Pistoia
24 km West · 10 km
49 months ago
14 Aug, 10:37
0.9
49 months ago
5 Aug, 05:47
1.7
49 months ago
17 Aug, 01:22

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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