All earthquakes
1.2
very light
EARTHQUAKE DETAILS

M1.2 earthquake · 3 km North of Laurino (SA)

5 years ago · 1 Jul 2021, 20:51

A very light earthquake, probably not felt by people. At this depth the shaking is felt, but rarely causes damage.

Stronger than 48% of Italian events in the past year

Where

3 km North of LaurinoEarthquakes 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

12 events
Magnitude:lightweakmoderatestrong

The energy released

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

1.0kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×501 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 ≈ 21 s

Animation sped up ~4× compared to reality.

  • Battipaglia
    45 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Potenza
    52 km from the epicentre
    first tremor in ~9 s
    main shaking in ~16 s
  • Salerno
    62 km from the epicentre
    first tremor in ~11 s
    main shaking in ~18 s
  • Cava de' Tirreni
    70 km from the epicentre
    first tremor in ~12 s
    main shaking in ~21 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

17 km
medium depth
2 times the height of Mount Everest

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

in line with 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?

Foreshock

In hindsight it was a foreshock: 5 years ago the same area had a stronger quake (M1.7). This can only be said after the fact — it was not predictable beforehand.

1.7
The mainshock
2 km North-West of Piaggine
5 years ago · 1 Jul 2021, 21:03
Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
5
last 30 days
2 before9 after
this quake
Strongest of the sequence1.7

How often does it happen here?

about every ~15 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 288 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 · 41 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
15616.7
Vallo di Diano earthquake
19 August 1561 · 28 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
15616.3
Vallo di Diano earthquake
31 July 1561 · 35 km from here
IX-XCompletely destructive: most buildings are destroyed.
14666.0
Irpinia-Basilicata earthquake
15 January 1466 · 48 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

Irpinia-Agri Valley

The epicentre lies about 25 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

1.5
2 km North-West of Piaggine
3 km East · 18 km
5 years ago
1 Jul 2021, 20:55
1.7
2 km North-West of Piaggine
4 km East · 17 km
5 years ago
1 Jul 2021, 21:03
1.7
3 km North-West of Piaggine
3 km East · 17 km
5 years ago
1 Jul 2021, 21:04
0.9
4 km North-West of Atena Lucana
23 km North-East · 20 km
5 years ago
7 Jul 2021, 05:27
1.2
1 km North-East of Laurino
2 km South · 10 km
5 years ago
25 Jun 2021, 20:06
1.5
3 km North-East of Laurino
1 km East · 18 km
5 years ago
25 Jun 2021, 17:56
1.0
1 km East of Sant'Angelo Le Fratte
30 km North-East · 19 km
5 years ago
9 Jul 2021, 14:37
1.4
2 km West of Salvitelle
30 km North · 11 km
5 years ago
9 Jul 2021, 16:50
0.5
4 km South of Brienza
25 km North-East · 10 km
5 years ago
12 Jul 2021, 02:50
0.7
5 years ago
21 Jul 2021, 00:33

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).