All earthquakes
1.4
very light
EARTHQUAKE DETAILS

M1.4 earthquake · 4 km North-West of Castrovillari (CS)

9 years ago · 7 Jan 2017, 18:25

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 63% of Italian events in the past year

Where

4 km North-West of CastrovillariEarthquakes in the province of CosenzaEarthquakes in Calabria

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.

1.9kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×251 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 ≈ 29 s

Animation sped up ~5× compared to reality.

  • Corigliano-Rossano
    32 km from the epicentre
    first tremor in ~6 s
    main shaking in ~10 s
  • Cosenza
    64 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Potenza
    96 km from the epicentre
    first tremor in ~16 s
    main shaking in ~28 s
  • Lamezia Terme
    99 km from the epicentre
    first tremor in ~17 s
    main shaking in ~29 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 (~18 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: 9 years ago the same area had a stronger quake (M1.9). This can only be said after the fact — it was not predictable beforehand.

1.9
The mainshock
3 km South-East of Rotonda
9 years ago · 12 Jan 2017, 12:43
Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
9
last 30 days
3 before3 after
this quake
Strongest of the sequence1.9

How often does it happen here?

about every ~16 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 268 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.

18365.9
Appennino lucano earthquake
20 November 1836 · 50 km from here
IXDestructive: many buildings partly or fully collapse.
19135.6
Calabria settentrionale earthquake
28 June 1913 · 36 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
17085.6
Pollino earthquake
26 January 1708 · 13 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
18875.5
Calabria settentrionale earthquake
3 December 1887 · 32 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

Pollino

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

estimated maximum magnitude 6.4between 1 and 10 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
7 km East of Mormanno
17 km West · 10 km
9 years ago
4 Jan 2017, 04:13
1.7
5 km East of Rotonda
12 km North-West · 34 km
9 years ago
4 Jan 2017, 04:09
1.4
5 km West of Morano Calabro
14 km West · 10 km
9 years ago
4 Jan 2017, 03:59
1.9
3 km South-East of Rotonda
14 km West · 8 km
9 years ago
12 Jan 2017, 12:43
1.7
3 km East of Laino Borgo
24 km North-West · 8 km
9 years ago
23 Jan 2017, 22:52
1.7
1 km North-West of Viggianello
18 km North-West · 17 km
9 years ago
3 Feb 2017, 21:08

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).