All earthquakes
0.8
very light
EARTHQUAKE DETAILS

2 km North-East of Bagno di Romagna

96 months ago · 3 Aug, 07:21

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 16% of Italian events in the past year

Where

2 km North-East of Bagno di RomagnaEarthquakes in the province of Forlì-CesenaEarthquakes 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

61 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.2kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×1,995 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 ≈ 14 s

Animation sped up ~3× compared to reality.

  • Cesena
    31 km from the epicentre
    first tremor in ~5 s
    main shaking in ~9 s
  • Forlì
    37 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Faenza
    46 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Rimini
    47 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 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?

Foreshock

In hindsight it was a foreshock: 95 months ago the same area had a stronger quake (M2.2). This can only be said after the fact — it was not predictable beforehand.

2.2
The mainshock
6 km South-West of Bibbiena
95 months ago · 15 Aug, 13:12
Activity in the area right now (30 km radius)
0
last 24 hours
2
last 7 days
23
last 30 days
115 before19 after
this quake
Strongest of the sequence2.2

How often does it happen here?

about every ~6 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 663 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.

19196.4
Mugello earthquake
29 June 1919 · 40 km from here
XCompletely destructive: most buildings are destroyed.
13526.3
Alta Valtiberina earthquake
25 December 1352 · 48 km from here
IXDestructive: many buildings partly or fully collapse.
17816.1
Faentino earthquake
4 April 1781 · 43 km from here
IX-XCompletely destructive: most buildings are destroyed.
16616.0
Appennino forlivese earthquake
22 March 1661 · 16 km from here
XCompletely destructive: most buildings are destroyed.

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

The closest seismic structure

Mugello-Citta' di Castello-Leonessa

The epicentre lies about 17 km from Mugello-Citta' di Castello-Leonessa, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.9between 1 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

1.2
3 km North of San Godenzo
27 km West · 8 km
96 months ago
2 Aug, 18:31
1.3
2 km South-East of Verghereto
14 km South-East · 9 km
96 months ago
4 Aug, 05:04
0.9
6 km West of Casteldelci
14 km South-East · 10 km
96 months ago
4 Aug, 10:46
1.8
3 km South-West of Galeata
13 km North-West · 10 km
96 months ago
5 Aug, 09:39
1.2
5 km West of Galeata
14 km North-West · 10 km
96 months ago
5 Aug, 11:44
1.0
96 months ago
5 Aug, 16:50
1.3
2 km South-East of Verghereto
14 km South-East · 9 km
96 months ago
31 Jul, 21:35
1.9
2 km South-East of Verghereto
14 km South-East · 9 km
96 months ago
31 Jul, 07:49
1.1
6 km West of Casteldelci
14 km South-East · 10 km
96 months ago
31 Jul, 07:13
1.3
2 km South-East of Verghereto
13 km South-East · 10 km
96 months ago
31 Jul, 06:45

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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