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2.0
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EARTHQUAKE DETAILS

M2.0 earthquake · 4 km East of Aliano (MT)

3 years ago · 30 Sept 2023, 06:40

A light earthquake, rarely felt by people. At this depth the shaking is felt, but rarely causes damage.

Stronger than 88% of Italian events in the past year

Where

4 km East of AlianoEarthquakes 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.

15kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×32 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.

  • Matera
    54 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • Potenza
    57 km from the epicentre
    first tremor in ~11 s
    main shaking in ~18 s
  • Altamura
    65 km from the epicentre
    first tremor in ~12 s
    main shaking in ~20 s
  • Corigliano-Rossano
    76 km from the epicentre
    first tremor in ~13 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

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 (~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?

Isolated quake

In the 30 days around this event no other quakes were recorded within 30 km: a one-off episode, very common in Italy.

Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
3
last 30 days
3 before3 after
this quake
Strongest of the sequence1.3

How often does it happen here?

about every ~19 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 225 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 · 38 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
18365.9
Appennino lucano earthquake
20 November 1836 · 47 km from here
IXDestructive: many buildings partly or fully collapse.
17085.6
Pollino earthquake
26 January 1708 · 44 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
19985.5
Appennino lucano earthquake
9 September 1998 · 39 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

Irpinia-Agri Valley

The epicentre lies about 31 km from Irpinia-Agri Valley, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.8between 1 and 14 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

1.3
3 years ago
10 Oct 2023, 19:49
1.3
4 km South-West of Accettura
24 km North-West · 17 km
3 years ago
12 Oct 2023, 13:48
0.8
4 km East of Teana
21 km South-West · 10 km
3 years ago
14 Sept 2023, 04:26
0.5
5 km South-West of Pietrapertosa
29 km North-West · 17 km
3 years ago
12 Sept 2023, 23:56
1.3
2 years ago
18 Oct 2023, 19:05
1.1
3 years ago
9 Sept 2023, 03:22

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).