All earthquakes
4.0
moderate
EARTHQUAKE DETAILS

3 km West of Visso

111 months ago · 27 Apr, 23:19

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

No. 4 of the month in ItalyStronger than 99% of Italian events in the past yearNo. 2 of the year in MarcheThe strongest of the past 12 months within 50 km

Where

3 km West of VissoEarthquakes in the province of MacerataEarthquakes in Marche

How far away could it be felt?

An estimate of how far people may have felt this quake.

  • up to ~18 km · felt by many people, especially on upper floors
    ≈ 9,000 people live in this area
  • up to ~44 km · felt only by some, at rest
    ≈ 430,000 people live in this area

The coloured rings on the map below show these distances.

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.

15tof TNT equivalent
63 lightning bolts
M3
×32 the energy of a magnitude 3 earthquake
M3this quakeM5

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.

  • Foligno
    20 km from the epicentre
    first tremor in ~4 s
    main shaking in ~6 s
  • Terni
    52 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • Perugia
    60 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • Teramo
    63 km from the epicentre
    first tremor in ~11 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

8 km
shallow

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?

Mainshock

It is the strongest quake of its sequence: so far it has been followed by 2000 aftershocks within 30 km. Aftershocks tend to fade in number and strength over time.

Activity in the area right now (30 km radius)
9
last 24 hours
61
last 7 days
338
last 30 days
0 before2000 after
this quake
Strongest of the sequence3.3

How often does it happen here?

about every ~2 months

Within 50 km of this epicentre, a magnitude ≥ 4 earthquake has occurred on average this often: 69 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 · 27 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
20166.6
Valnerina earthquake
30 October 2016 · 15 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
13286.5
Valnerina earthquake
1 December 1328 · 11 km from here
XCompletely destructive: most buildings are destroyed.
18326.4
Valle Umbra earthquake
13 January 1832 · 36 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

Muccia-Castelluccio di Norcia

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

estimated maximum magnitude 6.9between 2 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

1.3
111 months ago
3 May, 20:50
1.7
1 km North-West of Ussita
9 km East · 10 km
111 months ago
3 May, 21:02
1.5
5 km South of Valfornace
10 km North-East · 8 km
111 months ago
3 May, 21:38
1.5
6 km South of Valfornace
10 km North-East · 9 km
111 months ago
3 May, 21:39
1.0
111 months ago
3 May, 22:01
1.0
111 months ago
3 May, 22:17
0.9
6 km East of Foligno
14 km West · 9 km
111 months ago
3 May, 22:26
0.7
3 km South-West of Caldarola
19 km North-East · 9 km
111 months ago
3 May, 22:30
1.5
5 km East of Pieve Torina
8 km North-East · 9 km
111 months ago
3 May, 22:43
1.6
4 km East of Pieve Torina
7 km North-East · 9 km
111 months ago
3 May, 22:45

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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