All earthquakes
0.9
very light
EARTHQUAKE DETAILS

5 km East of Genga

35 months ago · 3 Aug, 22:15

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

5 km East of GengaEarthquakes in the province of AnconaEarthquakes in Marche

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 ≈ 15 s

Animation sped up ~3× compared to reality.

  • Ancona
    44 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Fano
    45 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Foligno
    49 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Pesaro
    53 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 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 (~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: 35 months ago the same area had a stronger quake (M3.4). This can only be said after the fact — it was not predictable beforehand.

3.4
The mainshock
3 km North-East of San Severino Marche
35 months ago · 5 Aug, 06:32
Activity in the area right now (30 km radius)
3
last 24 hours
24
last 7 days
96
last 30 days
97 before94 after
this quake
Strongest of the sequence3.4

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: 3732 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.

17816.5
Cagliese earthquake
3 June 1781 · 44 km from here
XCompletely destructive: most buildings are destroyed.
17516.4
Appennino umbro-marchigiano earthquake
27 July 1751 · 28 km from here
XCompletely destructive: most buildings are destroyed.
12796.2
Appennino umbro-marchigiano earthquake
30 April 1279 · 36 km from here
XCompletely destructive: most buildings are destroyed.
17996.2
Appennino marchigiano earthquake
28 July 1799 · 26 km from here
IX-XCompletely destructive: most buildings are destroyed.

Source: Parametric Catalogue of Italian Earthquakes CPTI15 (INGV, CC BY 4.0).

The closest seismic structure

Urbino-Camerino

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

estimated maximum magnitude 6.9between 3 and 9 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
2 km South-West of Sigillo
23 km West · 8 km
35 months ago
3 Aug, 19:24
0.9
2 km North of Sigillo
21 km West · 14 km
35 months ago
3 Aug, 17:08
1.2
2 km North of Sigillo
21 km West · 13 km
35 months ago
3 Aug, 16:14
0.2
35 months ago
4 Aug, 04:41
0.8
35 months ago
4 Aug, 15:18
1.1
5 km West of Costacciaro
29 km West · 11 km
35 months ago
3 Aug, 00:24
3.4
35 months ago
5 Aug, 06:32
1.5
35 months ago
5 Aug, 07:03
1.2
3 km West of Fossato di Vico
25 km West · 10 km
35 months ago
2 Aug, 12:09
1.5
3 km North of San Severino Marche
18 km South-East · 24 km
35 months ago
5 Aug, 09:23

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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