All earthquakes
1.8
very light
EARTHQUAKE DETAILS

Tirreno Meridionale [Mare]

24 months ago · 17 Sept, 18:43

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 82% of Italian events in the past year

Where

Tirreno Meridionale [Mare]Earthquakes in the province of CosenzaEarthquakes in Calabria

Epicentre at sea

The epicentre is at sea: for the same magnitude, the shaking is felt less on land, because the energy fades along the way before reaching the coast.

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

4 events
Magnitude:lightweakmoderatestrong

The energy released

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

7.6kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×63 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 ≈ 34 s

Animation sped up ~6× compared to reality.

  • Cosenza
    82 km from the epicentre
    first tremor in ~14 s
    main shaking in ~24 s
  • Corigliano-Rossano
    88 km from the epicentre
    first tremor in ~15 s
    main shaking in ~25 s
  • Lamezia Terme
    103 km from the epicentre
    first tremor in ~17 s
    main shaking in ~30 s
  • Battipaglia
    118 km from the epicentre
    first tremor in ~20 s
    main shaking in ~34 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

8 km
shallow

At only a few km deep the shaking is felt more sharply at the surface.

shallower than the area average (~91 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 (M2.7, 25 months ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.7
The mainshock
Tirreno Meridionale [Mare]
25 months ago · 21 Aug, 20:59
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
0
last 30 days
2 before1 after
this quake
Strongest of the sequence2.7

How often does it happen here?

about every ~10 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 444 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.

19775.9
Golfo di Policastro earthquake
30 December 1977 · 43 km from here
19985.4
Tirreno meridionale earthquake
18 May 1998 · 43 km from here
19905.3
Tirreno meridionale earthquake
14 December 1990 · 28 km from here
20085.2
Tirreno meridionale earthquake
17 December 2008 · 40 km from here

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

The closest seismic structure

Rimendiello-Mormanno

The epicentre lies about 59 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

1.6
Tirreno Meridionale [Mare]
13 km East · 82 km
24 months ago
12 Sept, 01:07
2.3
23 months ago
1 Oct, 01:49
2.7
Tirreno Meridionale [Mare]
7 km North-East · 285 km
25 months ago
21 Aug, 20:59

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).

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