M1.5 earthquake · 3 km South-East of Ottana (NU)
A very light earthquake, probably not felt by people. At only a few km deep the shaking is felt more sharply at the surface.
Where
3 km South-East of OttanaEarthquakes in the province of NuoroEarthquakes in SardegnaHow 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 eventsThe energy released
How much energy this quake unleashed, translated into everyday comparisons.
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.
Animation sped up ~6× compared to reality.
- Sassari84 km from the epicentrefirst tremor in ~14 smain shaking in ~24 s
- Olbia91 km from the epicentrefirst tremor in ~15 smain shaking in ~26 s
- Cagliari109 km from the epicentrefirst tremor in ~18 smain shaking in ~31 s
- Quartu Sant'Elena112 km from the epicentrefirst tremor in ~19 smain shaking in ~32 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
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?
It is an aftershock: it follows a stronger quake (M1.7, 3 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.
The closest seismic structure
The epicentre lies about 203 km from Northern Africa offshore - East, one of the seismic structures mapped by INGV geologists.
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
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).