All earthquakes
0.9
very light
EARTHQUAKE DETAILS

6 km South-East of Preci

113 months ago · 11 Mar, 10:09

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 22% of Italian events in the past year

Where

6 km South-East of PreciEarthquakes in the province of PerugiaEarthquakes in Umbria

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.

0.3kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×1,413 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 ≈ 19 s

Animation sped up ~3× compared to reality.

  • Foligno
    27 km from the epicentre
    first tremor in ~5 s
    main shaking in ~8 s
  • Terni
    42 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Teramo
    56 km from the epicentre
    first tremor in ~9 s
    main shaking in ~16 s
  • L'Aquila
    65 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 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 (~11 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: 112 months ago the same area had a stronger quake (M3.2). This can only be said after the fact — it was not predictable beforehand.

3.2
The mainshock
6 km South of Valfornace
112 months ago · 9 Apr, 22:31
Activity in the area right now (30 km radius)
10
last 24 hours
56
last 7 days
340
last 30 days
0 before2000 after
this quake
Strongest of the sequence3.2

How often does it happen here?

about every ~1 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 16045 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.

17036.9
Valnerina earthquake
14 January 1703 · 13 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17036.7
Aquilano earthquake
2 February 1703 · 47 km from here
XCompletely destructive: most buildings are destroyed.
20166.6
Valnerina earthquake
30 October 2016 · 4 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
13286.5
Valnerina earthquake
1 December 1328 · 5 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

Colfiorito-Cittareale

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

estimated maximum magnitude 7.1between 3 and 14 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

1.1
2 km North-East of Preci
7 km North · 11 km
112 months ago
21 Mar, 15:36
1.3
112 months ago
21 Mar, 15:45
1.5
6 km North-East of Norcia
9 km East · 11 km
112 months ago
21 Mar, 15:48
1.3
3 km South-East of Muccia
26 km North · 9 km
112 months ago
21 Mar, 16:33
0.5
6 km East of Cittareale
26 km South-East · 16 km
112 months ago
21 Mar, 16:41
1.0
4 km South of Muccia
24 km North · 6 km
112 months ago
21 Mar, 16:56
1.5
6 km West of Norcia
6 km South · 11 km
112 months ago
21 Mar, 17:22
1.8
3 km North-West of Accumoli
18 km South-East · 13 km
112 months ago
21 Mar, 17:24
1.0
6 km West of Norcia
6 km South · 11 km
112 months ago
21 Mar, 17:37
1.3
6 km South of Monte Cavallo
14 km North-West · 11 km
112 months ago
21 Mar, 17:38

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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