All earthquakes
1.2
very light
EARTHQUAKE DETAILS

M1.2 earthquake · 3 km South-West of Zocca (MO)

9 years ago · 23 Jul 2017, 16:43

A very light earthquake, probably not felt by people. At this depth the shaking is felt, but rarely causes damage.

Stronger than 48% of Italian events in the past year

Where

3 km South-West of ZoccaEarthquakes in the province of ModenaEarthquakes in Emilia-Romagna

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.

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 ≈ 15 s

Animation sped up ~3× compared to reality.

  • Bologna
    33 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Pistoia
    38 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Modena
    41 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Reggio nell'Emilia
    49 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

18 km
medium depth
2 times the height of Mount Everest

At this depth the shaking is felt, but rarely causes damage.

in line with 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?

Aftershock

It is an aftershock: it follows a stronger quake (M2.1, 9 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.1
The mainshock
4 km East of Camugnano
9 years ago · 17 Jul 2017, 03:49
Activity in the area right now (30 km radius)
0
last 24 hours
4
last 7 days
11
last 30 days
12 before11 after
this quake
Strongest of the sequence2.1

How often does it happen here?

about every ~5 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 945 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.

15016.0
Modenese earthquake
5 June 1501 · 23 km from here
IXDestructive: many buildings partly or fully collapse.
15426.0
Mugello earthquake
13 June 1542 · 49 km from here
IXDestructive: many buildings partly or fully collapse.
17255.7
Appennino tosco-emiliano earthquake
29 October 1725 · 50 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
17405.6
Garfagnana earthquake
6 March 1740 · 49 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

Castelvetro di Modena-Castel San Pietro Terme

The epicentre lies about 9 km from Castelvetro di Modena-Castel San Pietro Terme, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.8between 2 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

1.5
5 km South-West of Zocca
2 km South · 16 km
9 years ago
22 Jul 2017, 23:12
1.1
3 km North of Castel d'Aiano
5 km South-East · 16 km
9 years ago
19 Jul 2017, 13:23
1.6
5 km South of Monzuno
25 km East · 31 km
9 years ago
29 Jul 2017, 18:18
2.1
4 km East of Camugnano
23 km South-East · 11 km
9 years ago
17 Jul 2017, 03:49
1.7
9 years ago
17 Jul 2017, 03:46
1.6
4 km East of Camugnano
24 km South-East · 11 km
9 years ago
17 Jul 2017, 03:41
1.3
3 km North-West of Montese
8 km South-West · 16 km
9 years ago
31 Jul 2017, 02:37
1.4
4 km North of Sestola
16 km West · 22 km
9 years ago
31 Jul 2017, 12:53
1.7
5 km North of Montese
5 km South-West · 15 km
9 years ago
2 Aug 2017, 18:31
1.3
1 km West of Palagano
28 km West · 8 km
9 years ago
12 Jul 2017, 10:32

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).