All earthquakes
1.0
very light
EARTHQUAKE DETAILS

M1.0 earthquake · 3 km South-East of Piaggine (SA)

9 years ago · 17 Aug 2017, 06:52

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 31% of Italian events in the past year

Where

3 km South-East of PiaggineEarthquakes 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

18 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.5kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×1,000 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 ≈ 22 s

Animation sped up ~4× compared to reality.

  • Potenza
    50 km from the epicentre
    first tremor in ~8 s
    main shaking in ~15 s
  • Battipaglia
    52 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • Salerno
    69 km from the epicentre
    first tremor in ~12 s
    main shaking in ~20 s
  • Cava de' Tirreni
    77 km from the epicentre
    first tremor in ~13 s
    main shaking in ~22 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 (~16 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 (M1.5, 9 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

1.5
The mainshock
2 km South-East of Sanza
9 years ago · 9 Aug 2017, 15:53
Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
5
last 30 days
13 before4 after
this quake
Strongest of the sequence1.5

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: 306 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 · 34 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
15616.7
Vallo di Diano earthquake
19 August 1561 · 29 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
15616.3
Vallo di Diano earthquake
31 July 1561 · 39 km from here
IX-XCompletely destructive: most buildings are destroyed.
19775.9
Golfo di Policastro earthquake
30 December 1977 · 36 km from here

Source: Parametric Catalogue of Italian Earthquakes CPTI15 (INGV, CC BY 4.0).

The closest seismic structure

Irpinia-Agri Valley

The epicentre lies about 21 km from Irpinia-Agri Valley, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.8between 1 and 14 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
3 km North of Campora
12 km West · 9 km
9 years ago
19 Aug 2017, 04:58
1.2
3 km North-West of Atena Lucana
21 km North-East · 8 km
9 years ago
14 Aug 2017, 13:08
1.1
3 km South-East of Brienza
24 km North-East · 15 km
9 years ago
21 Aug 2017, 15:20
0.8
3 km East of Paterno
29 km East · 10 km
9 years ago
12 Aug 2017, 03:00
1.5
2 km South-East of Sanza
12 km South-East · 10 km
9 years ago
9 Aug 2017, 15:53
0.4
3 km North-East of Campora
10 km West · 10 km
9 years ago
9 Aug 2017, 10:26
0.9
1 km South of Satriano di Lucania
30 km North-East · 21 km
9 years ago
9 Aug 2017, 08:57
1.1
3 km South of Sanza
12 km South-East · 11 km
9 years ago
9 Aug 2017, 07:36
1.4
3 km South-East of Sanza
12 km South-East · 11 km
9 years ago
9 Aug 2017, 03:35
0.9
5 km West of Paterno
23 km East · 6 km
9 years ago
5 Aug 2017, 09:29

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).