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2.2
light
EARTHQUAKE DETAILS

M2.2 earthquake · 3 km South-East of Aulla (MS)

8 years ago · 21 Jun 2018, 05:40

A light earthquake, rarely felt by people. At only a few km deep the shaking is felt more sharply at the surface.

Stronger than 92% of Italian events in the past year

Where

3 km South-East of AullaEarthquakes in the province of Massa-CarraraEarthquakes 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

23 events
Magnitude:lightweakmoderatestrong

The energy released

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

30kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×16 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 ≈ 12 s

Animation sped up ~2× compared to reality.

  • Carrara
    12 km from the epicentre
    first tremor in ~3 s
    main shaking in ~4 s
  • La Spezia
    17 km from the epicentre
    first tremor in ~3 s
    main shaking in ~6 s
  • Massa
    18 km from the epicentre
    first tremor in ~3 s
    main shaking in ~6 s
  • Viareggio
    40 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 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 (~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 (M2.4, 8 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.4
The mainshock
3 km South-East of Licciana Nardi
8 years ago · 16 Jun 2018, 11:21
Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
2
last 30 days
13 before9 after
this quake
Strongest of the sequence2.4

How often does it happen here?

about every ~11 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 401 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 · 20 km from here
XCompletely destructive: most buildings are destroyed.
18346.0
Val di Taro-Lunigiana earthquake
14 February 1834 · 31 km from here
IXDestructive: many buildings partly or fully collapse.
18375.9
Lunigiana earthquake
11 April 1837 · 13 km from here
XCompletely destructive: most buildings are destroyed.
17405.6
Garfagnana earthquake
6 March 1740 · 39 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

Lunigiana

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

estimated maximum magnitude 7.0between 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
3 km South-East of Aulla
0 km North-West · 10 km
8 years ago
21 Jun 2018, 02:39
0.9
8 years ago
24 Jun 2018, 21:09
2.0
3 km South of Licciana Nardi
10 km North · 9 km
8 years ago
17 Jun 2018, 13:21
2.0
3 km South of Licciana Nardi
10 km North-East · 10 km
8 years ago
16 Jun 2018, 15:37
1.2
3 km South-East of Licciana Nardi
10 km North-East · 10 km
8 years ago
16 Jun 2018, 13:46
2.4
3 km South-East of Licciana Nardi
10 km North-East · 8 km
8 years ago
16 Jun 2018, 11:21
1.4
2 km North-West of Bolano
11 km West · 10 km
8 years ago
14 Jun 2018, 16:01
1.3
2 km North of Bolano
11 km West · 9 km
8 years ago
14 Jun 2018, 12:51
1.2
3 km South of Licciana Nardi
10 km North · 10 km
8 years ago
12 Jun 2018, 22:41
1.3
3 km North-West of Stazzema
25 km South-East · 8 km
8 years ago
6 Jul 2018, 16:51

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).