All earthquakes
1.6
very light
EARTHQUAKE DETAILS

M1.6 earthquake · 1 km East of Riva del Garda (TN)

6 years ago · 17 Sept 2020, 22:31

A very light earthquake, probably not felt by people. At only a few km deep the shaking is felt more sharply at the surface.

Stronger than 74% of Italian events in the past year

Where

1 km East of Riva del GardaEarthquakes in the province of TrentoEarthquakes in Trentino-Alto Adige

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

13 events
Magnitude:lightweakmoderatestrong

The energy released

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

3.8kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×126 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 ≈ 19 s

Animation sped up ~4× compared to reality.

  • Trento
    29 km from the epicentre
    first tremor in ~5 s
    main shaking in ~9 s
  • Verona
    49 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Brescia
    61 km from the epicentre
    first tremor in ~10 s
    main shaking in ~18 s
  • Vicenza
    66 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 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

8 km
shallow

At only a few km deep the shaking is felt more sharply at the surface.

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?

Aftershock

It is an aftershock: it follows a stronger quake (M2.8, 6 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.8
The mainshock
2 km North-West of Tignale
6 years ago · 28 Aug 2020, 07:32
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
6
last 30 days
9 before3 after
this quake
Strongest of the sequence2.8

How often does it happen here?

about every ~33 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 132 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 · 42 km from here
IXDestructive: many buildings partly or fully collapse.
12225.7
Bresciano-Veronese earthquake
25 December 1222 · 41 km from here
19015.4
Garda occidentale earthquake
30 October 1901 · 41 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19325.2
Garda orientale earthquake
19 February 1932 · 27 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.

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

The closest seismic structure

Giudicarie

The epicentre sits above this source area: the deep structure where this area's earthquakes can originate.

estimated maximum magnitude 6.8between 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

1.6
5 km East of Ala
24 km South-East · 11 km
6 years ago
16 Sept 2020, 11:16
1.3
2 km North-East of Tignale
14 km South-West · 9 km
6 years ago
19 Sept 2020, 18:36
1.4
5 km South-East of Brentonico
16 km South-East · 10 km
6 years ago
10 Sept 2020, 03:27
0.7
6 years ago
9 Sept 2020, 13:02
1.4
5 km South-East of Brentonico
14 km South-East · 13 km
6 years ago
26 Sept 2020, 13:43
1.4
3 km North-West of Magasa
20 km West · 6 km
6 years ago
6 Oct 2020, 11:13
1.2
6 km East of Vallarsa
29 km East · 11 km
6 years ago
29 Aug 2020, 18:01
2.8
2 km North-West of Tignale
16 km South-West · 11 km
6 years ago
28 Aug 2020, 07:32
0.9
4 km North-West of Ala
18 km South-East · 13 km
6 years ago
26 Aug 2020, 22:16
1.2
5 km North-West of Ala
17 km South-East · 13 km
6 years ago
26 Aug 2020, 22:14

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).