All earthquakes
0.3
very light
EARTHQUAKE DETAILS

M0.3 earthquake · 5 km South-East of Sapri (SA)

8 years ago · 1 Aug 2018, 03:23

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 0% of Italian events in the past year

Where

5 km South-East of SapriEarthquakes 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

10 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.1kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×11,220 its energy
M-1this quakeM1

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 ≈ 28 s

Animation sped up ~5× compared to reality.

  • Potenza
    69 km from the epicentre
    first tremor in ~12 s
    main shaking in ~20 s
  • Corigliano-Rossano
    79 km from the epicentre
    first tremor in ~13 s
    main shaking in ~23 s
  • Battipaglia
    87 km from the epicentre
    first tremor in ~15 s
    main shaking in ~25 s
  • Cosenza
    99 km from the epicentre
    first tremor in ~17 s
    main shaking in ~28 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

4 km
shallow

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?

Aftershock

It is an aftershock: it follows a stronger quake (M3.3, 8 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

3.3
The mainshock
9 km West of Praia a Mare
8 years ago · 21 Jul 2018, 11:27
Activity in the area right now (30 km radius)
0
last 24 hours
3
last 7 days
10
last 30 days
3 before6 after
this quake
Strongest of the sequence3.3

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: 346 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 · 37 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
19775.9
Golfo di Policastro earthquake
30 December 1977 · 22 km from here
18365.9
Appennino lucano earthquake
20 November 1836 · 13 km from here
IXDestructive: many buildings partly or fully collapse.
17085.6
Pollino earthquake
26 January 1708 · 38 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 17 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

0.6
3 km South of Castelsaraceno
26 km East · 19 km
8 years ago
10 Aug 2018, 00:38
3.3
9 km West of Praia a Mare
17 km South · 286 km
8 years ago
21 Jul 2018, 11:27
0.8
13 km West of Maratea
15 km South-West · 9 km
8 years ago
21 Jul 2018, 08:10
0.9
8 years ago
12 Aug 2018, 04:59
1.4
11 km South of Ispani
13 km South-West · 10 km
8 years ago
14 Aug 2018, 15:49
1.4
1 km East of Torraca
7 km North-West · 10 km
8 years ago
14 Aug 2018, 17:55
1.7
3 km South of Rivello
3 km East · 9 km
8 years ago
9 Jul 2018, 08:04
0.5
4 km East of Sapri
4 km North · 9 km
8 years ago
24 Aug 2018, 18:13
0.7
6 km North-East of Nemoli
17 km North-East · 17 km
8 years ago
27 Aug 2018, 20:51

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).