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2.6
light
EARTHQUAKE DETAILS

M2.6 earthquake · 20 km North of Crosia (CS)

8 years ago · 30 Aug 2018, 11:43

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

Stronger than 96% of Italian events in the past year

Where

20 km North of CrosiaEarthquakes in the province of CosenzaEarthquakes in Calabria

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

2 events
Magnitude:lightweakmoderatestrong

The energy released

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

120kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×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 ≈ 27 s

Animation sped up ~5× compared to reality.

  • Corigliano-Rossano
    32 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Cosenza
    69 km from the epicentre
    first tremor in ~12 s
    main shaking in ~20 s
  • Crotone
    78 km from the epicentre
    first tremor in ~13 s
    main shaking in ~23 s
  • Taranto
    94 km from the epicentre
    first tremor in ~16 s
    main shaking in ~27 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

18 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 (~21 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
0
last 7 days
2
last 30 days
1 before0 after
this quake
Strongest of the sequence1.2

How often does it happen here?

about every ~53 days

Within 50 km of this epicentre, a magnitude ≥ 2.5 earthquake has occurred on average this often: 81 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.

18366.2
Calabria settentrionale earthquake
25 April 1836 · 22 km from here
XCompletely destructive: most buildings are destroyed.
19175.3
Golfo di Taranto earthquake
12 June 1917 · 3 km from here
VRather strong: felt by almost everyone; hanging objects swing.
18245.3
Sila Greca earthquake
11 December 1824 · 29 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19884.9
Golfo di Taranto earthquake
13 April 1988 · 13 km from here
VI-VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.

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

The closest seismic structure

Amendolara

The epicentre sits above this source area: the deep structure where this area's earthquakes can originate.

estimated maximum magnitude 6.7between 1 and 10 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

1.2
6 km East of Calopezzati
24 km South-East · 11 km
8 years ago
3 Aug 2018, 08:04

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).