All earthquakes
1.1
very light
EARTHQUAKE DETAILS

M1.1 earthquake · 2 km North-West of Minucciano (LU)

9 years ago · 2 Dec 2016, 17:15

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 39% of Italian events in the past year

Where

2 km North-West of MinuccianoEarthquakes in the province of LuccaEarthquakes 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

24 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.7kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×708 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 ≈ 10 s

Animation sped up ~2× compared to reality.

  • Carrara
    13 km from the epicentre
    first tremor in ~3 s
    main shaking in ~4 s
  • Massa
    14 km from the epicentre
    first tremor in ~3 s
    main shaking in ~5 s
  • La Spezia
    31 km from the epicentre
    first tremor in ~5 s
    main shaking in ~9 s
  • Viareggio
    35 km from the epicentre
    first tremor in ~6 s
    main shaking in ~10 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 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?

Foreshock

In hindsight it was a foreshock: 9 years ago the same area had a stronger quake (M3.9). This can only be said after the fact — it was not predictable beforehand.

3.9
The mainshock
4 km North-East of Villa Minozzo
9 years ago · 9 Dec 2016, 08:21
Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
5
last 30 days
11 before12 after
this quake
Strongest of the sequence3.9

How often does it happen here?

about every ~9 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 496 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 · 6 km from here
XCompletely destructive: most buildings are destroyed.
18346.0
Val di Taro-Lunigiana earthquake
14 February 1834 · 40 km from here
IXDestructive: many buildings partly or fully collapse.
18375.9
Lunigiana earthquake
11 April 1837 · 2 km from here
XCompletely destructive: most buildings are destroyed.
17405.6
Garfagnana earthquake
6 March 1740 · 25 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 sits above this source area: the deep structure where this area's earthquakes can originate.

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

1.4
9 years ago
3 Dec 2016, 03:03
1.4
9 years ago
30 Nov 2016, 10:39
1.6
1 km South-West of Minucciano
2 km South-East · 8 km
9 years ago
29 Nov 2016, 06:49
1.3
5 km East of Frassinoro
29 km East · 16 km
9 years ago
6 Dec 2016, 18:03
1.4
2 km North of Barga
24 km East · 11 km
9 years ago
28 Nov 2016, 15:47
1.7
1 km West of Barga
23 km East · 11 km
9 years ago
28 Nov 2016, 15:44
3.9
4 km North-East of Villa Minozzo
28 km North-East · 10 km
9 years ago
9 Dec 2016, 08:21
1.6
9 years ago
10 Dec 2016, 10:07
1.5
5 km East of Frassinoro
29 km East · 11 km
9 years ago
24 Nov 2016, 20:36
1.3
9 years ago
24 Nov 2016, 01:16

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).