All earthquakes
0.7
very light
EARTHQUAKE DETAILS

6 km East of Gualdo Tadino

38 months ago · 21 Apr, 00:26

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 11% of Italian events in the past year

Where

6 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 ×2,818 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 ~4× compared to reality.

  • Foligno
    29 km from the epicentre
    first tremor in ~5 s
    main shaking in ~9 s
  • Perugia
    41 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Fano
    64 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Ancona
    66 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

9 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 (M2.9, 39 months ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.9
The mainshock
4 km North of Genga
39 months ago · 3 Apr, 00:57
Activity in the area right now (30 km radius)
2
last 24 hours
38
last 7 days
174
last 30 days
189 before218 after
this quake
Strongest of the sequence2.9

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: 6649 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 · 46 km from here
XCompletely destructive: most buildings are destroyed.
13286.5
Valnerina earthquake
1 December 1328 · 46 km from here
XCompletely destructive: most buildings are destroyed.
18326.4
Valle Umbra earthquake
13 January 1832 · 34 km from here
XCompletely destructive: most buildings are destroyed.
17516.4
Appennino umbro-marchigiano earthquake
27 July 1751 · 7 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

Piandimeleto-Bavareto

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

estimated maximum magnitude 7.1between 1 and 10 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
38 months ago
20 Apr, 21:46
0.3
38 months ago
21 Apr, 04:40
0.5
3 km North-East of Muccia
25 km South-East · 13 km
38 months ago
21 Apr, 05:18
0.5
9 km East of Gualdo Tadino
5 km South-East · 16 km
38 months ago
21 Apr, 06:35
0.6
6 km North-West of Fiuminata
5 km South-East · 15 km
38 months ago
21 Apr, 07:24
0.9
6 km North-West of Fiuminata
6 km South-East · 17 km
38 months ago
21 Apr, 08:01
0.2
9 km East of Gualdo Tadino
5 km South-East · 17 km
38 months ago
21 Apr, 08:02
0.6
5 km East of Sefro
20 km South-East · 13 km
38 months ago
21 Apr, 08:09
0.5
5 km North of Muccia
22 km South-East · 16 km
38 months ago
21 Apr, 11:26
0.6
38 months ago
20 Apr, 10:49

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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