All earthquakes
3.6
weak
EARTHQUAKE DETAILS

17 km West of Olivetta San Michele

18 months ago · 18 Mar, 18:45

A weak earthquake, felt by some of the population. At this depth the shaking is felt, but rarely causes damage.

No. 10 of the month in ItalyStronger than 99% of Italian events in the past yearNo. 1 of the year in LiguriaThe strongest of the past 12 months within 50 km

Where

17 km West of Olivetta San MicheleEarthquakes in the province of ImperiaEarthquakes in Liguria

How far away could it be felt?

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

  • up to ~21 km · felt only by some, at rest
    ≈ 25,000 people live in this area

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

13 events
Magnitude:lightweakmoderatestrong

The energy released

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

3.8tof TNT equivalent
16 lightning bolts
M3
×7.9 the energy of a magnitude 3 earthquake
M3this quakeM5

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 ≈ 37 s

Animation sped up ~7× compared to reality.

  • Sanremo
    37 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Cuneo
    65 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Savona
    105 km from the epicentre
    first tremor in ~18 s
    main shaking in ~31 s
  • Moncalieri
    128 km from the epicentre
    first tremor in ~22 s
    main shaking in ~37 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

20 km
medium depth
2.3 times the height of Mount Everest

At this depth the shaking is felt, but rarely causes damage.

deeper than 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?

Mainshock

It is the strongest quake of its sequence: so far it has been followed by 11 aftershocks within 30 km. Aftershocks tend to fade in number and strength over time.

Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
2
last 30 days
1 before11 after
this quake
Strongest of the sequence3.4

How often does it happen here?

It is the first magnitude ≥ 3.5 earthquake recorded within 50 km since 2014, the start of our archive.

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.

15645.8
Lantosque earthquake
20 July 1564 · 19 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
16445.7
Alpes Niçoises earthquake
15 February 1644 · 15 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
16185.6
Alpes Niçoises earthquake
18 January 1618 · 12 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
18315.6
Liguria occidentale earthquake
26 May 1831 · 43 km from here
VIII-IXDestructive: many buildings partly or fully collapse.

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

The closest seismic structure

Imperia Promontory

The epicentre lies about 30 km from Imperia Promontory, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.4between 3 and 15 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

1.7
18 km West of Olivetta San Michele
1 km North-West · 10 km
17 months ago
18 Mar, 18:55
1.7
18 km West of Olivetta San Michele
1 km North-West · 10 km
17 months ago
18 Mar, 22:05
3.4
18 km West of Olivetta San Michele
1 km North-West · 11 km
17 months ago
18 Mar, 22:24
2.7
17 months ago
20 Mar, 22:25
1.5
17 months ago
20 Mar, 23:08
1.1
Confine Italia-Francia (FRANCIA)
15 km North-West · 7 km
18 months ago
12 Mar, 22:20
1.5
17 km West of Olivetta San Michele
0 km North-West · 11 km
17 months ago
30 Mar, 18:11
1.1
17 km West of Olivetta San Michele
1 km North-East · 19 km
17 months ago
4 Apr, 22:11
0.9
4 km North-West of Pigna
26 km East · 11 km
17 months ago
11 Apr, 22:13
0.7
17 months ago
12 Apr, 02:41

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).

We use cookies to analyse site traffic and improve your experience.

Privacy PolicyCookie Policy