All earthquakes
1.3
very light
EARTHQUAKE DETAILS

M1.3 earthquake · 2 km South-West of San Chirico Raparo (PZ)

5 years ago · 16 May 2021, 16:18

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 55% of Italian events in the past year

Where

2 km South-West of San Chirico RaparoEarthquakes 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

28 events
Magnitude:lightweakmoderatestrong

The energy released

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

1.3kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×355 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 ≈ 24 s

Animation sped up ~4× compared to reality.

  • Potenza
    56 km from the epicentre
    first tremor in ~9 s
    main shaking in ~16 s
  • Corigliano-Rossano
    72 km from the epicentre
    first tremor in ~12 s
    main shaking in ~21 s
  • Matera
    74 km from the epicentre
    first tremor in ~12 s
    main shaking in ~21 s
  • Altamura
    83 km from the epicentre
    first tremor in ~14 s
    main shaking in ~24 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

9 km
shallow
1.1 times the height of Mount Everest

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?

Aftershock

It is an aftershock: it follows a stronger quake (M2.5, 5 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.5
The mainshock
5 km North of Lauria
5 years ago · 28 Apr 2021, 03:15
Activity in the area right now (30 km radius)
0
last 24 hours
2
last 7 days
9
last 30 days
21 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: 294 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 · 25 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
18365.9
Appennino lucano earthquake
20 November 1836 · 25 km from here
IXDestructive: many buildings partly or fully collapse.
18265.7
Potentino earthquake
1 February 1826 · 45 km from here
IXDestructive: many buildings partly or fully collapse.
17085.6
Pollino earthquake
26 January 1708 · 30 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

Rimendiello-Mormanno

The epicentre lies about 13 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

1.8
2 km East of San Martino d'Agri
6 km North-East · 18 km
5 years ago
16 May 2021, 11:27
1.3
5 years ago
14 May 2021, 00:42
1.4
4 km North of Moliterno
19 km West · 9 km
5 years ago
14 May 2021, 00:39
1.4
3 km West of Carbone
6 km South · 11 km
5 years ago
19 May 2021, 20:12
0.9
3 km North of Lagonegro
24 km West · 11 km
5 years ago
25 May 2021, 07:07
1.3
4 km West of Grumento Nova
22 km North-West · 10 km
5 years ago
26 May 2021, 22:36
0.7
4 km North of Lauria
17 km South-West · 15 km
5 years ago
4 May 2021, 21:20
1.9
5 km North-West of Lauria
19 km South-West · 9 km
5 years ago
3 May 2021, 20:36
1.2
5 km North of Lauria
17 km South-West · 13 km
5 years ago
1 May 2021, 16:35
1.4
5 km North of Lauria
17 km South-West · 15 km
5 years ago
1 May 2021, 09:11

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).