All earthquakes
3.5
weak
EARTHQUAKE DETAILS

18 km North-East of Piuro

120 months ago · 7 Oct, 09:27

A weak earthquake, felt by some of the population. At only a few km deep the shaking is felt more sharply at the surface.

No. 10 of the month in ItalyStronger than 99% of Italian events in the past yearNo. 2 of the year in LombardiaThe strongest of the past 12 months within 50 km

Where

18 km North-East of PiuroEarthquakes in the province of SondrioEarthquakes in Lombardia

How far away could it be felt?

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

  • up to ~5 km · felt by many people, especially on upper floors
  • up to ~24 km · felt only by some, at rest
    ≈ 4,000 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

6 events
Magnitude:lightweakmoderatestrong

The energy released

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

2.7tof TNT equivalent
11 lightning bolts
M3
×5.6 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 ≈ 31 s

Animation sped up ~6× compared to reality.

  • Como
    90 km from the epicentre
    first tremor in ~15 s
    main shaking in ~26 s
  • Bergamo
    95 km from the epicentre
    first tremor in ~16 s
    main shaking in ~27 s
  • Varese
    98 km from the epicentre
    first tremor in ~16 s
    main shaking in ~28 s
  • Monza
    109 km from the epicentre
    first tremor in ~18 s
    main shaking in ~31 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

10 km
shallow
1.1 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?

Mainshock

It is the strongest quake of its sequence: so far it has been followed by 4 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
1
last 7 days
1
last 30 days
1 before4 after
this quake
Strongest of the sequence2.0

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.

12956.2
Grigioni, Churwalden earthquake
3 September 1295 · 26 km from here
18275.0
Bassa Engadina, Ardez earthquake
2 April 1827 · 46 km from here
VIStrong: felt by everyone, many get scared; objects fall, first light damage to buildings.
16955.0
Grigioni, Region Praettigau earthquake
11 September 1695 · 38 km from here
18514.7
Valtellina earthquake
5 February 1851 · 47 km from here
V-VIStrong: felt by everyone, many get scared; objects fall, first light damage to 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 88 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).

Other quakes in the area

1.0
16 km North-East of Piuro
3 km South-East · 10 km
120 months ago
8 Oct, 11:42
0.9
17 km North-East of Piuro
2 km South-East · 11 km
120 months ago
9 Oct, 01:08
1.5
16 km North-East of Piuro
2 km South · 11 km
120 months ago
5 Oct, 12:05
1.5
17 km North-East of Piuro
2 km South · 11 km
120 months ago
14 Oct, 10:19
2.0
17 km North-East of Piuro
2 km West · 11 km
120 months ago
23 Oct, 06:23

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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