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2.6
light
EARTHQUAKE DETAILS

M2.6 earthquake · 7 km South-East of Poggio Rusco (MN)

11 years ago · 6 Aug 2015, 22:52

A light earthquake, rarely felt by people. At only a few km deep the shaking is felt more sharply at the surface.

Stronger than 96% of Italian events in the past yearNo. 5 of the year in Lombardia

Where

7 km South-East of Poggio RuscoEarthquakes in the province of MantovaEarthquakes in Lombardia

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

12 events
Magnitude:lightweakmoderatestrong

The energy released

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

120kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×4 its energy
M2this quakeM4

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 ≈ 14 s

Animation sped up ~3× compared to reality.

  • Carpi
    30 km from the epicentre
    first tremor in ~5 s
    main shaking in ~9 s
  • Modena
    37 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Ferrara
    37 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Rovigo
    47 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 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
1.1 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 (~12 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?

Foreshock

In hindsight it was a foreshock: 11 years ago the same area had a stronger quake (M2.7). This can only be said after the fact — it was not predictable beforehand.

2.7
The mainshock
4 km South-West of Vigarano Mainarda
11 years ago · 19 Aug 2015, 13:13
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
2
last 30 days
0 before11 after
this quake
Strongest of the sequence2.7

How often does it happen here?

about every ~51 days

Within 50 km of this epicentre, a magnitude ≥ 2.5 earthquake has occurred on average this often: 85 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.

11176.5
Veronese earthquake
3 January 1117 · 42 km from here
IXDestructive: many buildings partly or fully collapse.
20126.1
Pianura emiliana earthquake
20 May 2012 · 4 km from here
VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.
20125.9
Pianura emiliana earthquake
29 May 2012 · 17 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
15055.6
Bolognese earthquake
3 January 1505 · 47 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

Poggio Rusco-Migliarino

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

estimated maximum magnitude 6.8between 1 and 8 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

2.0
11 years ago
8 Aug 2015, 22:56
2.3
4 km West of Vigarano Mainarda
20 km South-East · 9 km
11 years ago
10 Aug 2015, 08:34
1.9
3 km West of Finale Emilia
11 km South · 29 km
11 years ago
12 Aug 2015, 21:05
2.1
11 years ago
19 Aug 2015, 10:33
2.5
4 km East of Terre del Reno
21 km South-East · 10 km
11 years ago
19 Aug 2015, 12:43
2.7
4 km South-West of Vigarano Mainarda
21 km South-East · 10 km
11 years ago
19 Aug 2015, 13:13
2.6
5 km South-West of Vigarano Mainarda
21 km South-East · 7 km
11 years ago
21 Aug 2015, 08:17
2.1
6 km North-East of Finale Emilia
6 km South-East · 9 km
11 years ago
23 Aug 2015, 19:10
2.3
4 km North-West of Poggio Renatico
22 km South-East · 7 km
11 years ago
29 Aug 2015, 14:44
2.2
3 km South-West of Vigarano Mainarda
22 km South-East · 10 km
11 years ago
3 Sept 2015, 10:16

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).