All earthquakes
1.1
very light
EARTHQUAKE DETAILS

4 km West of Sant'Angelo in Vado

35 months ago · 11 Aug, 14:22

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 38% of Italian events in the past year

Where

4 km West of Sant'Angelo in VadoEarthquakes in the province of Pesaro e UrbinoEarthquakes 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.

0.7kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×708 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 ≈ 14 s

Animation sped up ~3× compared to reality.

  • Rimini
    42 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Pesaro
    43 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Arezzo
    44 km from the epicentre
    first tremor in ~7 s
    main shaking in ~13 s
  • Cesena
    49 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 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

7 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: 34 months ago the same area had a stronger quake (M2.1). This can only be said after the fact — it was not predictable beforehand.

2.1
The mainshock
2 km South-West of Pieve Santo Stefano
34 months ago · 2 Sept, 17:09
Activity in the area right now (30 km radius)
0
last 24 hours
12
last 7 days
84
last 30 days
39 before42 after
this quake
Strongest of the sequence2.1

How often does it happen here?

about every ~8 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 555 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 · 14 km from here
XCompletely destructive: most buildings are destroyed.
13526.3
Alta Valtiberina earthquake
25 December 1352 · 30 km from here
IXDestructive: many buildings partly or fully collapse.
13896.0
Alta Valtiberina earthquake
18 October 1389 · 17 km from here
IXDestructive: many buildings partly or fully collapse.
19176.0
Alta Valtiberina earthquake
26 April 1917 · 30 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

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

1.2
4 km North of Montone
29 km South · 7 km
35 months ago
12 Aug, 00:32
0.2
8 km East of Pietralunga
30 km South-East · 7 km
35 months ago
12 Aug, 04:43
0.4
4 km East of Pietralunga
26 km South · 9 km
35 months ago
12 Aug, 07:05
0.9
35 months ago
12 Aug, 14:28
0.4
6 km South of Apecchio
19 km South · 8 km
35 months ago
13 Aug, 00:55
0.2
5 km East of Pietralunga
24 km South-East · 8 km
35 months ago
13 Aug, 01:05
0.4
7 km West of Pietralunga
24 km South · 6 km
35 months ago
13 Aug, 09:58
0.9
6 km South of Apecchio
19 km South · 7 km
35 months ago
13 Aug, 11:23
1.2
5 km West of Pietralunga
23 km South · 8 km
35 months ago
9 Aug, 10:38
1.3
35 months ago
13 Aug, 20:34

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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