All earthquakes
4.3
moderate
EARTHQUAKE DETAILS

4 km South-East of Castelsantangelo sul Nera

119 months ago · 3 Sept, 12:18

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. 14 of the year in ItalyStronger than 99% of Italian events in the past yearNo. 1 of the year in MarcheThe strongest of the past 12 months within 50 km

Where

4 km South-East of Castelsantangelo sul NeraEarthquakes 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 ~8 km · clearly felt by almost everyone
  • up to ~27 km · felt by many people, especially on upper floors
    ≈ 100,000 people live in this area
  • up to ~61 km · felt only by some, at rest
    ≈ 1.3m 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.

43tof TNT equivalent
178 lightning bolts
M3
×89 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 ≈ 19 s

Animation sped up ~3× compared to reality.

  • Foligno
    36 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Teramo
    46 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Terni
    55 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

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?

Isolated quake

In the 30 days around this event no other quakes were recorded within 30 km: a one-off episode, very common in Italy.

Activity in the area right now (30 km radius)
19
last 24 hours
65
last 7 days
321
last 30 days
0 before2000 after
this quake
Strongest of the sequence3.4

How often does it happen here?

about every ~56 days

Within 50 km of this epicentre, a magnitude ≥ 4 earthquake has occurred on average this often: 75 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.

17036.9
Valnerina earthquake
14 January 1703 · 21 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17036.7
Aquilano earthquake
2 February 1703 · 48 km from here
XCompletely destructive: most buildings are destroyed.
20166.6
Valnerina earthquake
30 October 2016 · 10 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
13286.5
Valnerina earthquake
1 December 1328 · 16 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

1.1
6 km West of Accumoli
18 km South · 11 km
118 months ago
24 Sept, 01:42
1.1
4 km East of Accumoli
18 km South-East · 6 km
118 months ago
24 Sept, 02:02
0.7
7 km South-West of Montemonaco
4 km South-East · 9 km
118 months ago
24 Sept, 02:12
1.3
6 km East of Cittareale
25 km South · 12 km
118 months ago
24 Sept, 02:14
0.8
2 km South-East of Amatrice
28 km South · 14 km
118 months ago
24 Sept, 02:24
1.4
5 km North of Cittareale
23 km South · 15 km
118 months ago
24 Sept, 02:59
1.2
2 km West of Norcia
12 km South-West · 10 km
118 months ago
24 Sept, 03:08
1.5
2 km North-West of Norcia
11 km South-West · 9 km
118 months ago
24 Sept, 03:19
1.1
4 km South-East of Accumoli
21 km South · 10 km
118 months ago
24 Sept, 03:21
0.9
118 months ago
24 Sept, 03:22

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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