All earthquakes
1.7
very light
EARTHQUAKE DETAILS

4 km North-West of Ferrandina

21 months ago · 7 Dec, 06:25

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

4 km North-West of FerrandinaEarthquakes in the province of MateraEarthquakes in Basilicata

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

58 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 ~4× compared to reality.

  • Matera
    30 km from the epicentre
    first tremor in ~6 s
    main shaking in ~10 s
  • Altamura
    41 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Potenza
    54 km from the epicentre
    first tremor in ~9 s
    main shaking in ~16 s
  • Bitonto
    65 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

18 km
medium depth
2 times the height of Mount Everest

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

in line with the area average (~16 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: 21 months ago the same area had a stronger quake (M2.4). This can only be said after the fact — it was not predictable beforehand.

2.4
The mainshock
5 km West of Ferrandina
21 months ago · 15 Dec, 00:54
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
3
last 30 days
19 before38 after
this quake
Strongest of the sequence2.4

How often does it happen here?

about every ~29 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 146 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.

18577.1
Basilicata earthquake
16 December 1857 · 50 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
19175.5
Val d'Agri earthquake
13 October 1917 · 44 km from here
VIStrong: felt by everyone, many get scared; objects fall, first light damage to buildings.
18575.3
Basilicata earthquake
26 December 1857 · 41 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
18465.2
Potentino earthquake
8 August 1846 · 23 km from here
VI-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

Baragiano-Palagianello

The epicentre lies about 17 km from Baragiano-Palagianello, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.4between 13 and 22 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

1.5
4 km North-West of Ferrandina
1 km South-West · 19 km
21 months ago
7 Dec, 06:22
1.8
21 months ago
7 Dec, 08:07
1.2
3 km North of Ferrandina
3 km East · 19 km
21 months ago
7 Dec, 10:54
1.7
21 months ago
8 Dec, 00:36
2.0
21 months ago
6 Dec, 02:50
1.6
4 km North of Ferrandina
4 km East · 18 km
21 months ago
8 Dec, 14:33
1.5
4 km North-West of Ferrandina
2 km North-East · 20 km
21 months ago
5 Dec, 08:21
1.6
21 months ago
5 Dec, 00:01
1.4
3 km North-West of Ferrandina
1 km South-East · 20 km
21 months ago
9 Dec, 21:54
1.5
21 months ago
9 Dec, 22:55

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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