All earthquakes
0.7
very light
EARTHQUAKE DETAILS

4 km North-West of Sarconi

8 days ago · 17 Aug, 15:46

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 11% of Italian events in the past year

Where

4 km North-West of SarconiEarthquakes 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

16 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.2kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×2,818 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 ≈ 25 s

Animation sped up ~5× compared to reality.

  • Potenza
    46 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Matera
    79 km from the epicentre
    first tremor in ~13 s
    main shaking in ~23 s
  • Corigliano-Rossano
    85 km from the epicentre
    first tremor in ~14 s
    main shaking in ~24 s
  • Altamura
    86 km from the epicentre
    first tremor in ~14 s
    main shaking in ~25 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

10 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 (M2.0, 1 month ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.0
The mainshock
1 km West of Paterno
1 month ago · 25 Jul, 12:24
Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
10
last 30 days
14 before1 after
nowthis quake
Strongest of the sequence2.0

How often does it happen here?

about every ~13 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 321 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 · 12 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
15616.7
Vallo di Diano earthquake
19 August 1561 · 47 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
19775.9
Golfo di Policastro earthquake
30 December 1977 · 48 km from here
18365.9
Appennino lucano earthquake
20 November 1836 · 16 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

Irpinia-Agri Valley

The epicentre sits above this source area: the deep structure where this area's earthquakes can originate.

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

1.1
7 km West of Castelsaraceno
11 km South · 10 km
8 days ago
17 Aug, 13:23
1.0
7 km West of Castelsaraceno
11 km South · 10 km
8 days ago
17 Aug, 13:01
1.1
6 days ago
19 Aug, 08:20
0.9
2 km North-West of Paterno
20 km North-West · 18 km
9 days ago
15 Aug, 20:31
0.8
7 km East of Sasso di Castalda
27 km North-West · 15 km
21 days ago
4 Aug, 17:46
1.3
21 days ago
4 Aug, 06:43
1.5
4 km North-East of Rivello
21 km South-West · 11 km
26 days ago
30 Jul, 11:56
1.3
4 km West of Nemoli
20 km South-West · 10 km
26 days ago
30 Jul, 11:50
1.1
2 km North-West of Sala Consilina
30 km North-West · 18 km
26 days ago
30 Jul, 06:49
1.2
1 km West of Paterno
18 km North-West · 10 km
1 month ago
25 Jul, 12:40

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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