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2.7
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EARTHQUAKE DETAILS

M2.7 earthquake · 2 km North-East of Cirigliano (MT)

6 years ago · 5 Aug 2020, 07:24

A light earthquake, rarely felt by people. At this depth the shaking is felt, but rarely causes damage.

Stronger than 97% of Italian events in the past yearNo. 4 of the year in Basilicata

Where

2 km North-East of CiriglianoEarthquakes 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

13 events
Magnitude:lightweakmoderatestrong

The energy released

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

169kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×2.8 its energy
M2this quakeM4

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
    39 km from the epicentre
    first tremor in ~7 s
    main shaking in ~13 s
  • Matera
    48 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • Altamura
    55 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • Bitonto
    78 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

19 km
medium depth
2.1 times the height of Mount Everest

At this depth the shaking is felt, but rarely causes damage.

in line with 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?

Mainshock

It is the strongest quake of its sequence: so far it has been followed by 6 aftershocks within 30 km. Aftershocks tend to fade in number and strength over time.

Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
9
last 30 days
6 before6 after
this quake
Strongest of the sequence2.0

How often does it happen here?

about every ~2 months

Within 50 km of this epicentre, a magnitude ≥ 2.5 earthquake has occurred on average this often: 64 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 · 29 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
18365.9
Appennino lucano earthquake
20 November 1836 · 47 km from here
IXDestructive: many buildings partly or fully collapse.
12735.8
Potenza earthquake
18 December 1273 · 38 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
19905.8
Potentino earthquake
5 May 1990 · 49 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

Baragiano-Palagianello

The epicentre lies about 25 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

1.4
8 km North-East of Salandra
24 km North-East · 10 km
6 years ago
7 Aug 2020, 15:07
1.5
8 km East of Salandra
24 km North-East · 11 km
6 years ago
7 Aug 2020, 18:37
1.0
6 km South of Irsina
28 km North · 27 km
6 years ago
31 Jul 2020, 00:32
1.9
4 km South of Brindisi Montagna
25 km North-West · 17 km
6 years ago
12 Aug 2020, 00:03
1.8
3 km East of Stigliano
18 km East · 19 km
6 years ago
21 Jul 2020, 00:34
1.8
4 km North-East of Stigliano
18 km East · 18 km
6 years ago
21 Jul 2020, 00:31
1.9
4 km North-East of Stigliano
18 km East · 22 km
6 years ago
27 Aug 2020, 17:18
1.0
4 km North-East of Stigliano
16 km East · 19 km
6 years ago
29 Aug 2020, 03:13
1.4
4 km North-East of Grumento Nova
26 km South-West · 20 km
6 years ago
31 Aug 2020, 14:18
1.4
6 years ago
9 Jul 2020, 20:38

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).