All earthquakes
1.4
very light
EARTHQUAKE DETAILS

M1.4 earthquake · 3 km East of Castelluccio Inferiore (PZ)

6 years ago · 25 Jul 2020, 22:50

A very light earthquake, probably not felt by people. At only a few km deep the shaking is felt more sharply at the surface.

Stronger than 63% of Italian events in the past year

Where

3 km East of Castelluccio InferioreEarthquakes 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

8 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 ≈ 26 s

Animation sped up ~5× compared to reality.

  • Corigliano-Rossano
    55 km from the epicentre
    first tremor in ~9 s
    main shaking in ~16 s
  • Potenza
    75 km from the epicentre
    first tremor in ~13 s
    main shaking in ~21 s
  • Cosenza
    84 km from the epicentre
    first tremor in ~14 s
    main shaking in ~24 s
  • Matera
    91 km from the epicentre
    first tremor in ~15 s
    main shaking in ~26 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 (~18 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: 6 years ago the same area had a stronger quake (M2.5). This can only be said after the fact — it was not predictable beforehand.

2.5
The mainshock
5 km West of Castelsaraceno
6 years ago · 7 Aug 2020, 15:34
Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
11
last 30 days
1 before6 after
this quake
Strongest of the sequence2.5

How often does it happen here?

about every ~15 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 290 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 · 41 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
18365.9
Appennino lucano earthquake
20 November 1836 · 27 km from here
IXDestructive: many buildings partly or fully collapse.
17085.6
Pollino earthquake
26 January 1708 · 11 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
19985.5
Appennino lucano earthquake
9 September 1998 · 10 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

Rimendiello-Mormanno

The epicentre lies about 4 km from Rimendiello-Mormanno, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.6between 1 and 12 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

2.0
6 years ago
3 Aug 2020, 14:52
1.1
2 km North-West of Saracena
26 km South · 11 km
6 years ago
13 Jul 2020, 22:30
1.4
3 km North of Lungro
27 km South · 8 km
6 years ago
7 Aug 2020, 01:12
1.9
4 km West of Castelsaraceno
21 km North-West · 13 km
6 years ago
7 Aug 2020, 10:52
2.5
5 km West of Castelsaraceno
21 km North-West · 14 km
6 years ago
7 Aug 2020, 15:34
1.1
1 km North of Sarconi
27 km North-West · 13 km
6 years ago
15 Aug 2020, 02:27
1.1
6 years ago
15 Aug 2020, 02:59

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).