All earthquakes
1.7
very light
EARTHQUAKE DETAILS

1 km West of Gropparello

101 months ago · 21 May, 23:45

A very light earthquake, probably not felt by people. At this depth the shaking is felt, but rarely causes damage.

Stronger than 78% of Italian events in the past year

Where

1 km West of GropparelloEarthquakes in the province of PiacenzaEarthquakes in Emilia-Romagna

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

25 events
Magnitude:lightweakmoderatestrong

The energy released

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

5.4kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×89 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 ~3× compared to reality.

  • Piacenza
    26 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Cremona
    44 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • Parma
    50 km from the epicentre
    first tremor in ~9 s
    main shaking in ~16 s
  • Pavia
    59 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

27 km
medium depth
3 times the height of Mount Everest

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

deeper than the area average (~17 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 (M3.9, 101 months ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

3.9
The mainshock
3 km West of Gropparello
101 months ago · 19 May, 18:41
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
2
last 30 days
19 before5 after
this quake
Strongest of the sequence3.9

How often does it happen here?

about every ~5 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 835 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.

18346.0
Val di Taro-Lunigiana earthquake
14 February 1834 · 45 km from here
IXDestructive: many buildings partly or fully collapse.
14385.6
Parmense earthquake
11 June 1438 · 42 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
15455.4
Val di Taro earthquake
9 June 1545 · 39 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
18985.4
Parmense earthquake
4 March 1898 · 47 km from here
VII-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

San Giorgio Piacentino-Fornovo di Taro

The epicentre lies about 3 km from San Giorgio Piacentino-Fornovo di Taro, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.2between 2 and 10 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
101 months ago
20 May, 01:40
1.8
1 km East of Gropparello
1 km East · 29 km
101 months ago
20 May, 01:33
2.1
5 km East of Ponte dell'Olio
5 km North · 23 km
101 months ago
20 May, 00:05
1.4
5 km East of Bettola
6 km South-West · 33 km
101 months ago
19 May, 22:45
3.0
2 km North of Gropparello
2 km North · 25 km
101 months ago
19 May, 22:06
1.4
2 km North of Gropparello
2 km North · 26 km
101 months ago
19 May, 22:03
1.5
4 km South-West of Gropparello
3 km South-West · 30 km
101 months ago
19 May, 21:18
2.2
2 km North-West of Gropparello
1 km North-West · 27 km
101 months ago
19 May, 20:00
2.2
3 km North of Gropparello
3 km North · 24 km
101 months ago
19 May, 19:32
1.9
4 km East of Ponte dell'Olio
4 km North · 25 km
101 months ago
19 May, 18:55

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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