All earthquakes
1.9
very light
EARTHQUAKE DETAILS

5 km South of Ragalna

88 months ago · 27 Mar, 05:32

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

5 km South of RagalnaEarthquakes in the province of CataniaEarthquakes in Sicilia

Volcanic area: Mount Etna

Here the ground shakes mostly because of moving magma and underground fluids, not colliding plates: events are typically shallow, frequent and organised in swarms. This activity is constantly monitored by INGV.

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

61 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 ≈ 23 s

Animation sped up ~4× compared to reality.

  • Catania
    17 km from the epicentre
    first tremor in ~3 s
    main shaking in ~5 s
  • Acireale
    18 km from the epicentre
    first tremor in ~3 s
    main shaking in ~6 s
  • Siracusa
    72 km from the epicentre
    first tremor in ~12 s
    main shaking in ~21 s
  • Modica
    79 km from the epicentre
    first tremor in ~13 s
    main shaking in ~23 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

7 km
shallow

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

shallower than the area average (~13 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?

Seismic swarm

It is part of a seismic swarm: many closely spaced quakes in the same area, with no dominant shock. A typical, well-known behaviour of some Italian areas.

3.0
The mainshock
2 km South-West of Mascali
88 months ago · 27 Mar, 18:14
Activity in the area right now (30 km radius)
0
last 24 hours
22
last 7 days
43
last 30 days
52 before57 after
this quake
Strongest of the sequence3.0

How often does it happen here?

about every ~2 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 2305 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.

15426.7
Sicilia sud-orientale earthquake
10 December 1542 · 45 km from here
XCompletely destructive: most buildings are destroyed.
11696.5
Sicilia sud-orientale earthquake
4 February 1169 · 45 km from here
XCompletely destructive: most buildings are destroyed.
18186.3
Catanese earthquake
20 February 1818 · 16 km from here
IX-XCompletely destructive: most buildings are destroyed.
16985.7
Monti Iblei settentrionali earthquake
1 January 1698 · 39 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.

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

The closest seismic structure

Gela-Catania

The epicentre lies about 4 km from Gela-Catania, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.1between 3 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

3.0
2 km South-West of Mascali
21 km North-East · 7 km
88 months ago
27 Mar, 18:14
1.4
3 km South-East of Milo
17 km North-East · 8 km
88 months ago
28 Mar, 03:31
1.9
13 km South-East of Aci Castello
30 km South-East · 10 km
88 months ago
28 Mar, 07:13
1.4
2 km South of Riposto
21 km East · 11 km
88 months ago
26 Mar, 03:34
1.9
3 km South of Zafferana Etnea
13 km North-East · 8 km
88 months ago
28 Mar, 09:39
2.0
5 km West of Sant'Alfio
16 km North-East · 4 km
88 months ago
28 Mar, 12:57
2.0
5 km West of Sant'Alfio
16 km North-East · 0 km
88 months ago
28 Mar, 13:01
1.8
3 km West of Milo
15 km North-East · 10 km
88 months ago
28 Mar, 18:28
1.9
0 km South-East of Milo
18 km North-East · 10 km
88 months ago
25 Mar, 16:04
1.9
4 km South of Ragalna
2 km North-West · 1 km
88 months ago
25 Mar, 15:59

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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