All earthquakes
1.0
very light
EARTHQUAKE DETAILS

2 km South-West of Pieve Santo Stefano

77 months ago · 9 Feb, 05:07

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 30% of Italian events in the past year

Where

2 km South-West of Pieve Santo StefanoEarthquakes in the province of ArezzoEarthquakes 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

37 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.5kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×1,000 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 ≈ 18 s

Animation sped up ~3× compared to reality.

  • Arezzo
    26 km from the epicentre
    first tremor in ~5 s
    main shaking in ~8 s
  • Cesena
    50 km from the epicentre
    first tremor in ~8 s
    main shaking in ~15 s
  • Rimini
    56 km from the epicentre
    first tremor in ~9 s
    main shaking in ~16 s
  • Forlì
    61 km from the epicentre
    first tremor in ~10 s
    main shaking in ~18 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 (~10 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 (M2.8, 78 months ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.8
The mainshock
3 km South-East of Borgo Pace
78 months ago · 14 Jan, 14:30
Activity in the area right now (30 km radius)
1
last 24 hours
7
last 7 days
38
last 30 days
27 before9 after
this quake
Strongest of the sequence2.8

How often does it happen here?

about every ~9 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 477 events in the last 11 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.

17816.5
Cagliese earthquake
3 June 1781 · 39 km from here
XCompletely destructive: most buildings are destroyed.
13526.3
Alta Valtiberina earthquake
25 December 1352 · 23 km from here
IXDestructive: many buildings partly or fully collapse.
16616.0
Appennino forlivese earthquake
22 March 1661 · 41 km from here
XCompletely destructive: most buildings are destroyed.
13896.0
Alta Valtiberina earthquake
18 October 1389 · 26 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

Mugello-Citta' di Castello-Leonessa

The epicentre lies about 1 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

1.0
77 months ago
9 Feb, 03:48
1.1
77 months ago
9 Feb, 03:38
1.3
77 months ago
7 Feb, 18:49
0.5
77 months ago
12 Feb, 04:11
1.0
77 months ago
15 Feb, 06:25
1.3
6 km South-East of Bagno di Romagna
19 km North-West · 8 km
77 months ago
2 Feb, 22:26
0.6
77 months ago
16 Feb, 09:48
0.7
4 km North of Casteldelci
20 km North-East · 7 km
77 months ago
17 Feb, 22:17
1.1
6 km North of Verghereto
21 km North · 11 km
77 months ago
18 Feb, 05:27
1.4
78 months ago
29 Jan, 00:02

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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