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2.7
light
EARTHQUAKE DETAILS

8 km North-East of Irsina

139 months ago · 20 Jan, 23:43

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

Stronger than 97% of Italian events in the past yearNo. 3 of the year in BasilicataThe strongest of the past 12 months within 50 km

Where

8 km North-East of IrsinaEarthquakes in the province of MateraEarthquakes in Basilicata

How far away could it be felt?

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

  • up to ~2 km · felt only by some, at rest

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

9 events
Magnitude:lightweakmoderatestrong

The energy released

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

169kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×2.8 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 ≈ 12 s

Animation sped up ~2× compared to reality.

  • Altamura
    20 km from the epicentre
    first tremor in ~4 s
    main shaking in ~6 s
  • Matera
    26 km from the epicentre
    first tremor in ~5 s
    main shaking in ~8 s
  • Bitonto
    40 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Andria
    41 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 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

7 km
shallow

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

shallower than 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?

Mainshock

It is the strongest quake of its sequence: so far it has been followed by 4 aftershocks within 30 km. Aftershocks tend to fade in number and strength over time.

Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
3
last 30 days
4 before4 after
this quake
Strongest of the sequence2.4

How often does it happen here?

about every ~3 months

Within 50 km of this epicentre, a magnitude ≥ 2.5 earthquake has occurred on average this often: 40 events in the last 11 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.

16255.8
Vulture earthquake
August 1625 · 46 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
12735.8
Potenza earthquake
18 December 1273 · 46 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
19905.8
Potentino earthquake
5 May 1990 · 48 km from here
VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.
19635.2
Potentino earthquake
13 February 1963 · 47 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

Baragiano-Palagianello

The epicentre lies about 13 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

1.8
139 months ago
22 Jan, 00:58
1.7
4 km South-West of Matera
26 km East · 16 km
139 months ago
22 Jan, 05:14
2.4
139 months ago
18 Jan, 13:15
2.1
3 km East of Garaguso
25 km South · 28 km
139 months ago
24 Jan, 08:12
2.1
3 km East of Garaguso
24 km South · 33 km
139 months ago
24 Jan, 14:21
1.6
139 months ago
16 Jan, 06:08
2.1
139 months ago
15 Jan, 00:55
2.2
139 months ago
12 Jan, 01:21

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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