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2.3
light
EARTHQUAKE DETAILS

M2.3 earthquake · 4 km South-West of Vigarano Mainarda (FE)

9 years ago · 29 Apr 2017, 17:02

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

Stronger than 93% of Italian events in the past year

Where

4 km South-West of Vigarano MainardaEarthquakes in the province of FerraraEarthquakes 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

16 events
Magnitude:lightweakmoderatestrong

The energy released

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

43kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×11 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 ≈ 13 s

Animation sped up ~2× compared to reality.

  • Ferrara
    18 km from the epicentre
    first tremor in ~3 s
    main shaking in ~6 s
  • Bologna
    37 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Rovigo
    39 km from the epicentre
    first tremor in ~7 s
    main shaking in ~11 s
  • Carpi
    43 km from the epicentre
    first tremor in ~7 s
    main shaking in ~13 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

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 (M3.2, 9 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

3.2
The mainshock
4 km North-East of Terre del Reno
9 years ago · 26 Apr 2017, 21:15
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
2
last 30 days
12 before3 after
this quake
Strongest of the sequence3.2

How often does it happen here?

about every ~19 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 229 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.

20126.1
Pianura emiliana earthquake
20 May 2012 · 17 km from here
VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.
20125.9
Pianura emiliana earthquake
29 May 2012 · 31 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
15055.6
Bolognese earthquake
3 January 1505 · 39 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
20125.5
Pianura emiliana earthquake
29 May 2012 · 38 km from here

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

The closest seismic structure

Finale Emilia-Mirabello

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

estimated maximum magnitude 6.3between 4 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

1.9
9 years ago
27 Apr 2017, 13:24
2.6
9 years ago
26 Apr 2017, 21:15
3.2
4 km North-East of Terre del Reno
3 km North-West · 8 km
9 years ago
26 Apr 2017, 21:15
2.6
4 km East of Terre del Reno
1 km South-West · 8 km
9 years ago
26 Apr 2017, 18:46
3.1
9 years ago
26 Apr 2017, 18:46
2.1
9 years ago
24 Apr 2017, 09:06
3.0
9 years ago
5 May 2017, 18:25
2.3
9 years ago
7 May 2017, 01:26
2.4
4 km West of Vigarano Mainarda
1 km North-West · 10 km
9 years ago
7 May 2017, 02:15
2.1
2 km North of Finale Emilia
15 km West · 7 km
9 years ago
20 Apr 2017, 21:29

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).