All earthquakes
1.7
very light
EARTHQUAKE DETAILS

5 km East of Cirigliano

138 months ago · 26 Feb, 09:56

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

5 km East of CiriglianoEarthquakes 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

7 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 ≈ 23 s

Animation sped up ~4× compared to reality.

  • Potenza
    42 km from the epicentre
    first tremor in ~8 s
    main shaking in ~15 s
  • Matera
    45 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • Altamura
    53 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • Bitonto
    77 km from the epicentre
    first tremor in ~14 s
    main shaking in ~23 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

28 km
medium depth
3.2 times the height of Mount Everest

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

deeper than the area average (~15 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: 137 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
4 km North-East of Craco
137 months ago · 25 Mar, 12:38
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
10
last 30 days
4 before2 after
this quake
Strongest of the sequence2.4

How often does it happen here?

about every ~17 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 245 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.

18577.1
Basilicata earthquake
16 December 1857 · 33 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
18365.9
Appennino lucano earthquake
20 November 1836 · 50 km from here
IXDestructive: many buildings partly or fully collapse.
12735.8
Potenza earthquake
18 December 1273 · 41 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
18265.7
Potentino earthquake
1 February 1826 · 42 km from here
IXDestructive: many buildings partly or fully collapse.

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

The closest seismic structure

Baragiano-Palagianello

The epicentre lies about 24 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

1.2
3 km North of Spinoso
29 km South-West · 9 km
138 months ago
26 Feb, 04:15
1.5
138 months ago
23 Feb, 00:23
1.3
138 months ago
18 Feb, 16:50
1.5
2 km North-East of Garaguso
17 km North · 26 km
137 months ago
13 Mar, 16:40
2.2
4 km West of Ferrandina
16 km East · 11 km
138 months ago
5 Feb, 17:20
2.4
4 km North-East of Craco
22 km East · 44 km
137 months ago
25 Mar, 12:38

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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