All earthquakes
2.8
light
EARTHQUAKE DETAILS

12 km East of Sirolo

128 months ago · 2 Dec, 03:46

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

Stronger than 97% of Italian events in the past yearThe strongest of the past 12 months within 50 km

Where

12 km East of SiroloEarthquakes in the province of AnconaEarthquakes in Marche

How far away could it be felt?

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

  • up to ~5 km · felt only by some, at rest

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

7 events
Magnitude:lightweakmoderatestrong

The energy released

How much energy this quake unleashed, translated into everyday comparisons.

239kgof TNT equivalent
1.0 lightning bolt
M3
A magnitude 3 earthquake releases ×2 its energy
M2this quakeM4

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 ≈ 28 s

Animation sped up ~5× compared to reality.

  • Ancona
    21 km from the epicentre
    first tremor in ~4 s
    main shaking in ~6 s
  • Fano
    67 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Pesaro
    80 km from the epicentre
    first tremor in ~13 s
    main shaking in ~23 s
  • Foligno
    99 km from the epicentre
    first tremor in ~17 s
    main shaking in ~28 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.

shallower than the area average (~14 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 2 aftershocks within 30 km. Aftershocks tend to fade in number and strength over time.

Activity in the area right now (30 km radius)
1
last 24 hours
1
last 7 days
2
last 30 days
4 before2 after
this quake
Strongest of the sequence1.8

How often does it happen here?

about every ~2 months

Within 50 km of this epicentre, a magnitude ≥ 2.5 earthquake has occurred on average this often: 66 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.

19305.8
Senigallia earthquake
30 October 1930 · 32 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
16905.6
Costa anconetana earthquake
23 December 1690 · 12 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
12695.6
Costa anconetana earthquake
September 1269 · 14 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19175.2
Costa anconetana earthquake
5 November 1917 · 9 km from here
VI-VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.

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

The closest seismic structure

Conero offshore

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

estimated maximum magnitude 6.6between 2 and 7 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

1.4
13 km East of Numana
5 km South-East · 10 km
128 months ago
30 Nov, 03:28
1.3
12 km East of Numana
6 km South-East · 9 km
128 months ago
30 Nov, 03:24
1.8
13 km East of Numana
6 km South-East · 9 km
128 months ago
30 Nov, 01:52
1.2
3 km South-West of Offagna
26 km West · 31 km
128 months ago
5 Dec, 18:47
0.8
129 months ago
9 Nov, 03:07
1.7
3 km North of Montefano
28 km West · 33 km
127 months ago
31 Dec, 03:11

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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