All earthquakes
1.3
very light
EARTHQUAKE DETAILS

M1.3 earthquake · 4 km North-West of Accettura (MT)

5 years ago · 25 Jun 2021, 10:34

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

Stronger than 55% of Italian events in the past year

Where

4 km North-West of AccetturaEarthquakes 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.

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 ≈ 23 s

Animation sped up ~4× compared to reality.

  • Potenza
    31 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Matera
    46 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • Altamura
    50 km from the epicentre
    first tremor in ~11 s
    main shaking in ~18 s
  • Andria
    70 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

40 km
deep
4.5 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?

Aftershock

It is an aftershock: it follows a stronger quake (M2.7, 5 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.7
The mainshock
6 km South-West of Tolve
5 years ago · 1 Jun 2021, 11:11
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
7
last 30 days
4 before2 after
this quake
Strongest of the sequence2.7

How often does it happen here?

about every ~17 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 253 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 · 31 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
12735.8
Potenza earthquake
18 December 1273 · 30 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
19905.8
Potentino earthquake
5 May 1990 · 40 km from here
VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.
18265.7
Potentino earthquake
1 February 1826 · 34 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

Baragiano-Palagianello

The epicentre lies about 15 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

0.9
3 km East of Potenza
29 km North-West · 17 km
5 years ago
24 Jun 2021, 04:23
0.9
1 km South of Tricarico
13 km North · 24 km
5 years ago
29 Jun 2021, 04:12
2.5
3 km South-East of Grottole
24 km East · 28 km
5 years ago
2 Jul 2021, 18:16
1.1
3 km North of Pignola
29 km West · 19 km
5 years ago
3 Jun 2021, 11:10
2.7
6 km South-West of Tolve
18 km North-West · 30 km
5 years ago
1 Jun 2021, 11:11
1.9
6 km South-West of Tolve
19 km North-West · 30 km
5 years ago
1 Jun 2021, 11:08

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).