All earthquakes
1.8
very light
EARTHQUAKE DETAILS

M1.8 earthquake outside Italy

2 years ago · 27 Mar 2024, 23:52

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

Nearest Italian town: Campodolcino (SO)Earthquakes in the province of SondrioEarthquakes in Lombardia

Epicentre abroad

The epicentre lies outside Italy's borders. The quake appears here because the INGV seismic network also records events close to Italy, which can be felt on Italian territory.

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

1 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 ≈ 25 s

Animation sped up ~5× compared to reality.

  • Como
    64 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Varese
    68 km from the epicentre
    first tremor in ~11 s
    main shaking in ~20 s
  • Bergamo
    84 km from the epicentre
    first tremor in ~14 s
    main shaking in ~24 s
  • Gallarate
    86 km from the epicentre
    first tremor in ~14 s
    main shaking in ~25 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

9 km
shallow
1 times the height of Mount Everest

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?

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

No other quakes within 30 km in the 30 days around the event.

How often does it happen here?

about every ~10 months

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 14 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.

18514.7
Valtellina earthquake
5 February 1851 · 50 km from here
V-VIStrong: felt by everyone, many get scared; objects fall, first light damage to buildings.
19914.7
Grigioni, Vaz earthquake
20 November 1991 · 46 km from here
VIStrong: felt by everyone, many get scared; objects fall, first light damage to buildings.
15124.6
Valchiavenna earthquake
8 February 1512 · 16 km from here
VIStrong: felt by everyone, many get scared; objects fall, first light damage to buildings.
19174.6
Alta Engadina earthquake
9 December 1917 · 45 km from here
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

Western S-Alps internal thrust

The epicentre lies about 70 km from Western S-Alps internal thrust, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.9between 5 and 12 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).

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).