All earthquakes
1.2
very light
EARTHQUAKE DETAILS

3 km North-West of Vernio

71 months ago · 4 Nov, 07:05

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 47% of Italian events in the past year

Where

3 km North-West 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

16 events
Magnitude:lightweakmoderatestrong

The energy released

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

1.0kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×501 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 ≈ 14 s

Animation sped up ~3× compared to reality.

  • Pistoia
    21 km from the epicentre
    first tremor in ~4 s
    main shaking in ~7 s
  • Prato
    23 km from the epicentre
    first tremor in ~4 s
    main shaking in ~7 s
  • Firenze
    36 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Bologna
    48 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

10 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 (~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 (M2.0, 71 months ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.0
The mainshock
1 km South-East of Castiglione dei Pepoli
71 months ago · 27 Oct, 03:15
Activity in the area right now (30 km radius)
0
last 24 hours
3
last 7 days
10
last 30 days
7 before8 after
this quake
Strongest of the sequence2.0

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: 1027 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 · 32 km from here
XCompletely destructive: most buildings are destroyed.
15426.0
Mugello earthquake
13 June 1542 · 23 km from here
IXDestructive: many buildings partly or fully collapse.
17255.7
Appennino tosco-emiliano earthquake
29 October 1725 · 38 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19145.6
Lucchesia earthquake
27 October 1914 · 47 km from here
VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.

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

The closest seismic structure

Mugello-Citta' di Castello-Leonessa

The epicentre lies about 6 km from Mugello-Citta' di Castello-Leonessa, one of the seismic structures mapped by INGV geologists.

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

1.0
1 km West of Vernio
3 km South-East · 10 km
71 months ago
4 Nov, 07:15
1.4
71 months ago
4 Nov, 19:31
1.3
6 km West of Castel del Rio
26 km East · 10 km
71 months ago
30 Oct, 17:23
1.3
71 months ago
9 Nov, 01:10
1.7
71 months ago
10 Nov, 03:38
1.4
2 km South of Castiglione dei Pepoli
7 km North-East · 10 km
71 months ago
27 Oct, 03:32
2.0
71 months ago
27 Oct, 03:15
1.9
71 months ago
27 Oct, 03:15
1.5
5 km North-West of Cantagallo
7 km South-West · 10 km
71 months ago
24 Oct, 23:57
2.0
70 months ago
18 Nov, 04:52

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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