All earthquakes
1.4
very light
EARTHQUAKE DETAILS

M1.4 earthquake · 2 km South-East of Castelmezzano (PZ)

2 years ago · 20 Nov 2023, 12:25

A very light earthquake, probably not felt by people. Being deep, it is felt less at the surface.

Stronger than 63% of Italian events in the past year

Where

2 km South-East of CastelmezzanoEarthquakes in the province of PotenzaEarthquakes 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

32 events
Magnitude:lightweakmoderatestrong

The energy released

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

1.9kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×251 its energy
M0this quakeM2

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
    26 km from the epicentre
    first tremor in ~7 s
    main shaking in ~13 s
  • Matera
    53 km from the epicentre
    first tremor in ~11 s
    main shaking in ~18 s
  • Altamura
    57 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Andria
    73 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

35 km
deep
4 times the height of Mount Everest

Being deep, it is felt less at the surface.

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: 2 years ago the same area had a stronger quake (M2.6). This can only be said after the fact — it was not predictable beforehand.

2.6
The mainshock
0 km South of Pietrapertosa
2 years ago · 22 Nov 2023, 23:55
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
11
last 30 days
6 before25 after
this quake
Strongest of the sequence2.6

How often does it happen here?

about every ~16 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 273 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 · 24 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
15616.7
Vallo di Diano earthquake
19 August 1561 · 45 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
18365.9
Appennino lucano earthquake
20 November 1836 · 46 km from here
IXDestructive: many buildings partly or fully collapse.
12735.8
Potenza earthquake
18 December 1273 · 25 km from here
VIII-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 18 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

1.3
2 km West of Pietrapertosa
3 km South-East · 22 km
2 years ago
20 Nov 2023, 07:57
1.0
1 km South-West of Pietrapertosa
5 km South-East · 21 km
2 years ago
20 Nov 2023, 21:30
1.6
2 km West of Pietrapertosa
3 km East · 22 km
2 years ago
21 Nov 2023, 04:11
1.5
5 km South-East of Viggiano
23 km South-West · 12 km
2 years ago
19 Nov 2023, 16:45
1.9
2 km West of Pietrapertosa
3 km South-East · 20 km
2 years ago
21 Nov 2023, 20:31
1.4
5 km East of Laurenzana
6 km South · 10 km
2 years ago
21 Nov 2023, 21:37
1.7
2 km West of Pietrapertosa
3 km East · 18 km
2 years ago
22 Nov 2023, 01:14
1.3
3 km West of Pietrapertosa
2 km East · 23 km
2 years ago
22 Nov 2023, 02:04
1.7
2 km West of Pietrapertosa
3 km East · 23 km
2 years ago
22 Nov 2023, 02:24
1.4
1 km South of Pietrapertosa
5 km East · 23 km
2 years ago
22 Nov 2023, 02:50

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).