All earthquakes
1.9
very light
EARTHQUAKE DETAILS

M1.9 earthquake · 12 km South of Scicli (RG)

10 years ago · 23 Jun 2016, 15:59

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 85% of Italian events in the past year

Where

12 km South of ScicliEarthquakes in the province of RagusaEarthquakes in Sicilia

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

3 events
Magnitude:lightweakmoderatestrong

The energy released

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

11kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×45 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 ≈ 18 s

Animation sped up ~3× compared to reality.

  • Ragusa
    31 km from the epicentre
    first tremor in ~5 s
    main shaking in ~9 s
  • Modica
    32 km from the epicentre
    first tremor in ~5 s
    main shaking in ~9 s
  • Vittoria
    39 km from the epicentre
    first tremor in ~7 s
    main shaking in ~11 s
  • Siracusa
    62 km from the epicentre
    first tremor in ~10 s
    main shaking in ~18 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

6 km
shallow

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

shallower than the area average (~18 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
1
last 30 days
2 before0 after
this quake
Strongest of the sequence1.6

How often does it happen here?

about every ~33 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 132 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.

19495.1
Sicilia sud-orientale earthquake
8 October 1949 · 30 km from here
VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.
17174.9
Ragusano earthquake
4 April 1717 · 38 km from here
VI-VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.
18954.8
Monti Iblei ? earthquake
13 April 1895 · 48 km from here
VI-VIIVery strong: hard to stand; chimneys and roof tiles fall, serious damage to weaker buildings.
19904.8
Stretto di Sicilia earthquake
29 October 1990 · 46 km from here
VRather strong: felt by almost everyone; hanging objects swing.

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

The closest seismic structure

Scicli-Giarratana

The epicentre lies about 3 km from Scicli-Giarratana, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.0between 1 and 23 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
10 years ago
2 Jun 2016, 00:52
1.6
6 km South of Ragusa
25 km North · 21 km
10 years ago
24 May 2016, 20:20

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).