All earthquakes
1.8
very light
EARTHQUAKE DETAILS

3 km South of Orani

50 months ago · 27 Jul, 11:12

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 82% of Italian events in the past year

Where

3 km South of OraniEarthquakes in the province of NuoroEarthquakes in Sardegna

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

2 events
Magnitude:lightweakmoderatestrong

The energy released

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

7.6kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×63 its energy
M1this quakeM3

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 ≈ 33 s

Animation sped up ~6× compared to reality.

  • Olbia
    83 km from the epicentre
    first tremor in ~14 s
    main shaking in ~24 s
  • Sassari
    85 km from the epicentre
    first tremor in ~14 s
    main shaking in ~24 s
  • Cagliari
    114 km from the epicentre
    first tremor in ~19 s
    main shaking in ~33 s
  • Quartu Sant'Elena
    116 km from the epicentre
    first tremor in ~19 s
    main shaking in ~33 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

1 km
shallow

At only a few km deep the shaking is felt more sharply at the surface.

in line with the area average (~2 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)
0
last 24 hours
0
last 7 days
0
last 30 days
1 before0 after
this quake
Strongest of the sequence1.2

The closest seismic structure

Northern Africa offshore - East

The epicentre lies about 205 km from Northern Africa offshore - East, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 8.0between 1 and 25 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
3 km South-East of Ottana
9 km South-West · 1 km
50 months ago
8 Jul, 08:25

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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