All earthquakes
1.5
very light
EARTHQUAKE DETAILS

M1.5 earthquake · 3 km North of Maratea (PZ)

8 years ago · 3 Dec 2017, 11:13

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 69% of Italian events in the past year

Where

3 km North of MarateaEarthquakes 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

20 events
Magnitude:lightweakmoderatestrong

The energy released

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

2.7kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×178 its energy
M1this quakeM3

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 ≈ 27 s

Animation sped up ~5× compared to reality.

  • Potenza
    72 km from the epicentre
    first tremor in ~12 s
    main shaking in ~21 s
  • Corigliano-Rossano
    75 km from the epicentre
    first tremor in ~13 s
    main shaking in ~22 s
  • Battipaglia
    92 km from the epicentre
    first tremor in ~15 s
    main shaking in ~26 s
  • Cosenza
    94 km from the epicentre
    first tremor in ~16 s
    main shaking in ~27 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 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 (~20 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: 8 years ago the same area had a stronger quake (M2.6). This can only be said after the fact — it was not predictable beforehand.

2.6
The mainshock
15 km South-West of Maratea
8 years ago · 26 Dec 2017, 07:57
Activity in the area right now (30 km radius)
0
last 24 hours
3
last 7 days
12
last 30 days
14 before5 after
this quake
Strongest of the sequence2.6

How often does it happen here?

about every ~12 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 357 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 · 39 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
19775.9
Golfo di Policastro earthquake
30 December 1977 · 23 km from here
18365.9
Appennino lucano earthquake
20 November 1836 · 15 km from here
IXDestructive: many buildings partly or fully collapse.
17085.6
Pollino earthquake
26 January 1708 · 34 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 16 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

1.4
8 years ago
6 Dec 2017, 12:36
1.4
2 km South-West of Sapri
9 km North-West · 10 km
8 years ago
29 Nov 2017, 08:36
0.9
3 km South-West of Sapri
9 km West · 10 km
8 years ago
29 Nov 2017, 04:51
1.2
3 km South-West of Sapri
9 km West · 10 km
8 years ago
29 Nov 2017, 02:30
1.0
5 km South-East of Sanza
27 km North-West · 14 km
8 years ago
28 Nov 2017, 20:57
1.8
5 km South of Santa Domenica Talao
28 km South-East · 49 km
8 years ago
9 Dec 2017, 09:27
1.9
3 km East of Maratea
3 km South-East · 8 km
8 years ago
12 Dec 2017, 15:23
1.8
4 km South of Maratea
8 km South · 7 km
8 years ago
23 Nov 2017, 21:54
1.6
5 km West of Maratea
5 km West · 6 km
8 years ago
19 Nov 2017, 05:12
1.3
8 years ago
19 Nov 2017, 00:14

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).