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3.6
weak
EARTHQUAKE DETAILS

M3.6 earthquake · 4 km South-East of Vallarsa (TN)

9 years ago · 9 Feb 2017, 09:14

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

No. 4 of the month in ItalyStronger than 99% of Italian events in the past yearNo. 1 of the year in Trentino-Alto AdigeThe strongest of the past 12 months within 50 km

Where

4 km South-East of VallarsaEarthquakes in the province of TrentoEarthquakes in Trentino-Alto Adige

How far away could it be felt?

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

  • up to ~7 km · felt by many people, especially on upper floors
    ≈ 5,000 people live in this area
  • up to ~27 km · felt only by some, at rest
    ≈ 346,000 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

5 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 ≈ 21 s

Animation sped up ~4× compared to reality.

  • Trento
    30 km from the epicentre
    first tremor in ~5 s
    main shaking in ~9 s
  • Verona
    39 km from the epicentre
    first tremor in ~7 s
    main shaking in ~11 s
  • Vicenza
    40 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Padova
    71 km from the epicentre
    first tremor in ~12 s
    main shaking in ~21 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

11 km
medium depth
1.2 times the height of Mount Everest

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

in line with the area average (~7 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
2
last 7 days
5
last 30 days
2 before2 after
this quake
Strongest of the sequence1.5

How often does it happen here?

about every ~2.9 years

Within 50 km of this epicentre, a magnitude ≥ 3.5 earthquake has occurred on average this often: 4 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.

18915.9
Valle d'Illasi earthquake
7 June 1891 · 24 km from here
IXDestructive: many buildings partly or fully collapse.
12225.7
Bresciano-Veronese earthquake
25 December 1222 · 49 km from here
19325.2
Garda orientale earthquake
19 February 1932 · 36 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
18825.1
Monte Baldo earthquake
18 September 1882 · 30 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

Schio-Vicenza

The epicentre lies about 7 km from Schio-Vicenza, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.3between 1 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

1.1
9 years ago
29 Jan 2017, 03:02
1.5
1 km West of Vallarsa
4 km North-West · 14 km
9 years ago
25 Feb 2017, 12:35
1.3
4 km East of Brentonico
12 km West · 14 km
9 years ago
22 Jan 2017, 02:24
1.2
1 km East of Ala
8 km West · 11 km
9 years ago
5 Mar 2017, 04:01

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).