All earthquakes
0.8
very light
EARTHQUAKE DETAILS

3 km East of Gualdo Tadino

71 months ago · 2 Aug, 04:51

A very light earthquake, probably not felt by people. At this depth the shaking is felt, but rarely causes damage.

Stronger than 16% of Italian events in the past year

Where

3 km East of Gualdo TadinoEarthquakes 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.

0.2kgof 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 ≈ 21 s

Animation sped up ~4× compared to reality.

  • Foligno
    26 km from the epicentre
    first tremor in ~5 s
    main shaking in ~9 s
  • Perugia
    37 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Fano
    68 km from the epicentre
    first tremor in ~12 s
    main shaking in ~20 s
  • Ancona
    69 km from the epicentre
    first tremor in ~12 s
    main shaking in ~21 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

18 km
medium depth
2 times the height of Mount Everest

At this depth the shaking is felt, but rarely causes damage.

deeper than 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?

Foreshock

In hindsight it was a foreshock: 71 months ago the same area had a stronger quake (M3.1). This can only be said after the fact — it was not predictable beforehand.

3.1
The mainshock
5 km North of Cerreto d'Esi
71 months ago · 27 Aug, 04:46
Activity in the area right now (30 km radius)
5
last 24 hours
46
last 7 days
192
last 30 days
153 before208 after
this quake
Strongest of the sequence3.1

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: 6936 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.

17816.5
Cagliese earthquake
3 June 1781 · 47 km from here
XCompletely destructive: most buildings are destroyed.
13286.5
Valnerina earthquake
1 December 1328 · 44 km from here
XCompletely destructive: most buildings are destroyed.
18326.4
Valle Umbra earthquake
13 January 1832 · 30 km from here
XCompletely destructive: most buildings are destroyed.
17516.4
Appennino umbro-marchigiano earthquake
27 July 1751 · 4 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

1.2
6 km South-East of Nocera Umbra
15 km South-East · 10 km
71 months ago
2 Aug, 00:13
1.2
5 km West of Sassoferrato
23 km North · 14 km
71 months ago
2 Aug, 15:09
1.1
3 km East of Muccia
29 km South-East · 5 km
71 months ago
1 Aug, 16:06
0.7
6 km North-East of Gubbio
21 km North-West · 10 km
71 months ago
1 Aug, 14:01
0.5
1 km North-East of Costacciaro
19 km North-West · 10 km
71 months ago
3 Aug, 00:38
1.2
71 months ago
3 Aug, 01:24
0.7
2 km South of Costacciaro
17 km North-West · 11 km
71 months ago
3 Aug, 02:11
1.1
4 km North-East of Costacciaro
19 km North · 14 km
71 months ago
3 Aug, 02:29
1.3
7 km West of Costacciaro
23 km North-West · 11 km
71 months ago
3 Aug, 08:14
0.5
5 km East of Gagliole
28 km East · 11 km
71 months ago
1 Aug, 00:31

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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