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2.2
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EARTHQUAKE DETAILS

M2.2 earthquake · 6 km South-East of Casalbuono (SA)

8 years ago · 31 Oct 2017, 05:01

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

Stronger than 92% of Italian events in the past year

Where

6 km South-East of CasalbuonoEarthquakes in the province of SalernoEarthquakes in Campania

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

37 events
Magnitude:lightweakmoderatestrong

The energy released

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

30kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×16 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
    53 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • Battipaglia
    81 km from the epicentre
    first tremor in ~14 s
    main shaking in ~23 s
  • Corigliano-Rossano
    86 km from the epicentre
    first tremor in ~14 s
    main shaking in ~25 s
  • Matera
    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

10 km
medium depth
1.2 times the height of Mount Everest

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

shallower than the area average (~17 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 (M3.8, 8 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

3.8
The mainshock
5 km South-East of Padula
8 years ago · 27 Oct 2017, 00:38
Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
11
last 30 days
15 before21 after
this quake
Strongest of the sequence3.8

How often does it happen here?

about every ~14 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 301 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 · 20 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 · 34 km from here
18365.9
Appennino lucano earthquake
20 November 1836 · 5 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

Rimendiello-Mormanno

The epicentre lies about 6 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

0.7
7 km East of Casalbuono
1 km East · 11 km
8 years ago
31 Oct 2017, 05:09
0.8
7 km East of Casalbuono
1 km North-East · 11 km
8 years ago
31 Oct 2017, 05:13
1.4
8 years ago
30 Oct 2017, 14:29
1.0
8 years ago
30 Oct 2017, 13:34
1.6
8 years ago
30 Oct 2017, 08:37
0.8
4 km North of Casalbuono
10 km North-West · 11 km
8 years ago
30 Oct 2017, 08:10
1.2
3 km East of Maratea
23 km South · 9 km
8 years ago
29 Oct 2017, 05:28
1.1
8 years ago
2 Nov 2017, 20:43
0.6
4 km East of Padula
17 km North · 15 km
8 years ago
27 Oct 2017, 06:38
0.9
3 km South-East of Padula
15 km North-West · 13 km
8 years ago
27 Oct 2017, 06:30

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).