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EARTHQUAKE DETAILS

M2.0 earthquake · 3 km East of Meldola (FC)

10 years ago · 21 Aug 2016, 00:14

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

Stronger than 88% of Italian events in the past year

Where

3 km East of MeldolaEarthquakes 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

29 events
Magnitude:lightweakmoderatestrong

The energy released

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

15kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×32 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 ≈ 10 s

Animation sped up ~2× compared to reality.

  • Cesena
    10 km from the epicentre
    first tremor in ~2 s
    main shaking in ~4 s
  • Forlì
    13 km from the epicentre
    first tremor in ~3 s
    main shaking in ~4 s
  • Faenza
    27 km from the epicentre
    first tremor in ~5 s
    main shaking in ~8 s
  • Ravenna
    33 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

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: 10 years ago the same area had a stronger quake (M2.6). This can only be said after the fact — it was not predictable beforehand.

2.6
The mainshock
6 km South of Faenza
10 years ago · 12 Sept 2016, 12:25
Activity in the area right now (30 km radius)
0
last 24 hours
3
last 7 days
4
last 30 days
21 before7 after
this quake
Strongest of the sequence2.6

How often does it happen here?

about every ~7 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 625 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.

17816.1
Faentino earthquake
4 April 1781 · 29 km from here
IX-XCompletely destructive: most buildings are destroyed.
16616.0
Appennino forlivese earthquake
22 March 1661 · 18 km from here
XCompletely destructive: most buildings are destroyed.
17686.0
Appennino forlivese earthquake
19 October 1768 · 23 km from here
IXDestructive: many buildings partly or fully collapse.
15846.0
Appennino forlivese earthquake
10 September 1584 · 28 km from here
IXDestructive: many buildings partly or fully collapse.

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

The closest seismic structure

Castel San Pietro Terme-Meldola

The epicentre lies about 1 km from Castel San Pietro Terme-Meldola, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.5between 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

2.1
10 years ago
19 Aug 2016, 18:41
2.0
0 km East of Faenza
27 km North-West · 24 km
10 years ago
22 Aug 2016, 07:05
1.2
4 km North-East of Bagno di Romagna
24 km South-West · 10 km
10 years ago
22 Aug 2016, 10:50
1.5
2 km West of Meldola
4 km West · 29 km
10 years ago
18 Aug 2016, 12:35
1.8
2 km East of Meldola
0 km West · 24 km
10 years ago
17 Aug 2016, 13:27
1.4
3 km East of Sant'Agata Feltria
29 km South-East · 37 km
10 years ago
17 Aug 2016, 13:00
2.1
1 km West of Meldola
3 km West · 30 km
10 years ago
16 Aug 2016, 14:46
1.4
2 km South-East of Meldola
2 km South-West · 28 km
10 years ago
15 Aug 2016, 22:40
1.3
2 km South-West of Bertinoro
5 km North-East · 25 km
10 years ago
15 Aug 2016, 18:01
1.1
10 years ago
15 Aug 2016, 07:51

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).