All earthquakes
3.9
weak
EARTHQUAKE DETAILS

4 km North-East of Villa Minozzo

118 months ago · 9 Dec, 08:21

A weak earthquake, felt by some of the population. At only a few km deep the shaking is felt more sharply at the surface.

No. 4 of the month in ItalyStronger than 99% of Italian events in the past yearNo. 3 of the year in Emilia-RomagnaThe strongest of the past 12 months within 50 km

Where

4 km North-East of Villa MinozzoEarthquakes in the province of Reggio EmiliaEarthquakes in Emilia-Romagna

How far away could it be felt?

An estimate of how far people may have felt this quake.

  • up to ~15 km · felt by many people, especially on upper floors
    ≈ 34,000 people live in this area
  • up to ~39 km · felt only by some, at rest
    ≈ 391,000 people live in this area

The coloured rings on the map below show these distances.

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

26 events
Magnitude:lightweakmoderatestrong

The energy released

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

11tof TNT equivalent
45 lightning bolts
M3
×22 the energy of a magnitude 3 earthquake
M3this quakeM5

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 ≈ 15 s

Animation sped up ~3× compared to reality.

  • Massa
    40 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Carrara
    40 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Reggio nell'Emilia
    42 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Pistoia
    50 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 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.

shallower than the area average (~15 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 10 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
1
last 7 days
10
last 30 days
15 before10 after
this quake
Strongest of the sequence3.0

How often does it happen here?

about every ~8 months

Within 50 km of this epicentre, a magnitude ≥ 3.5 earthquake has occurred on average this often: 18 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.

19206.5
Garfagnana earthquake
7 September 1920 · 23 km from here
XCompletely destructive: most buildings are destroyed.
15016.0
Modenese earthquake
5 June 1501 · 36 km from here
IXDestructive: many buildings partly or fully collapse.
18375.9
Lunigiana earthquake
11 April 1837 · 30 km from here
XCompletely destructive: most buildings are destroyed.
17405.6
Garfagnana earthquake
6 March 1740 · 29 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

Garfagnana

The epicentre lies about 15 km from Garfagnana, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.9between 1 and 10 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
3 km South-West of Piazza al Serchio
23 km South-West · 9 km
118 months ago
10 Dec, 10:07
1.3
5 km East of Frassinoro
14 km South-East · 16 km
118 months ago
6 Dec, 18:03
0.8
3 km West of Piazza al Serchio
24 km South-West · 10 km
118 months ago
12 Dec, 09:23
0.8
118 months ago
13 Dec, 17:27
1.4
2 km North-West of Minucciano
27 km South-West · 8 km
118 months ago
3 Dec, 03:03
1.1
2 km North-West of Minucciano
28 km South-West · 9 km
118 months ago
2 Dec, 17:15
1.6
1 km South-West of Minucciano
28 km South-West · 8 km
119 months ago
29 Nov, 06:49
1.4
2 km North of Barga
25 km South · 11 km
119 months ago
28 Nov, 15:47
1.7
1 km West of Barga
26 km South · 11 km
119 months ago
28 Nov, 15:44
0.8
118 months ago
22 Dec, 00:55

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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