All earthquakes
2.9
light
EARTHQUAKE DETAILS

M2.9 offshore earthquake

9 years ago · 12 Sept 2017, 00:44

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

Stronger than 98% of Italian events in the past year

Where

Nearest Italian town: Diamante (CS)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?

An estimate of how far people may have felt this quake.

  • up to ~6 km · felt only by some, at rest

The coloured rings on the map below show these distances.

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

5 events
Magnitude:lightweakmoderatestrong

The energy released

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

338kgof TNT equivalent
1.4 lightning bolts
M3
A magnitude 3 earthquake releases ×1.4 its energy
M2this quakeM4

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 ≈ 37 s

Animation sped up ~7× compared to reality.

  • Cosenza
    90 km from the epicentre
    first tremor in ~15 s
    main shaking in ~26 s
  • Lamezia Terme
    103 km from the epicentre
    first tremor in ~17 s
    main shaking in ~30 s
  • Corigliano-Rossano
    106 km from the epicentre
    first tremor in ~18 s
    main shaking in ~30 s
  • Catanzaro
    130 km from the epicentre
    first tremor in ~22 s
    main shaking in ~37 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

11 km
medium depth
1.3 times the height of Mount Everest

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

shallower than the area average (~133 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?

Isolated quake

In the 30 days around this event no other quakes were recorded within 30 km: a one-off episode, very common in Italy.

Activity in the area right now (30 km radius)
0
last 24 hours
1
last 7 days
2
last 30 days
2 before2 after
this quake
Strongest of the sequence2.8

How often does it happen here?

about every ~15 days

Within 50 km of this epicentre, a magnitude ≥ 2.5 earthquake has occurred on average this often: 282 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.

19945.8
Tirreno meridionale earthquake
5 January 1994 · 27 km from here
IV-VRather strong: felt by almost everyone; hanging objects swing.
19985.4
Tirreno meridionale earthquake
18 May 1998 · 16 km from here
19905.3
Tirreno meridionale earthquake
14 December 1990 · 11 km from here
20085.2
Tirreno meridionale earthquake
17 December 2008 · 26 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 84 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

2.3
Tirreno Meridionale [Mare]
21 km North-East · 270 km
9 years ago
22 Sept 2017, 02:04
2.8
Tirreno Meridionale [Mare]
11 km East · 296 km
9 years ago
22 Aug 2017, 01:44
2.3
Tirreno Meridionale [Mare]
22 km South · 273 km
9 years ago
21 Aug 2017, 04:49
2.3
Tirreno Meridionale [Mare]
12 km South-East · 13 km
9 years ago
5 Oct 2017, 01:09

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).