All earthquakes
1.2
very light
EARTHQUAKE DETAILS

3 km North of Ragalna

124 months ago · 19 Apr, 23:05

A very light earthquake, probably not felt by people. At this depth the shaking is felt, but rarely causes damage.

Stronger than 47% of Italian events in the past year

Where

3 km North 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

26 events
Magnitude:lightweakmoderatestrong

The energy released

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

1.0kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×501 its energy
M0this quakeM2

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.

  • Acireale
    19 km from the epicentre
    first tremor in ~4 s
    main shaking in ~7 s
  • Catania
    24 km from the epicentre
    first tremor in ~5 s
    main shaking in ~9 s
  • Messina
    75 km from the epicentre
    first tremor in ~13 s
    main shaking in ~22 s
  • Siracusa
    79 km from the epicentre
    first tremor in ~14 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

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 (~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.

2.4
The mainshock
1 km East of Giarre
123 months ago · 27 Apr, 01:56
Activity in the area right now (30 km radius)
2
last 24 hours
27
last 7 days
51
last 30 days
14 before11 after
this quake
Strongest of the sequence2.4

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: 2468 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.

18186.3
Catanese earthquake
20 February 1818 · 18 km from here
IX-XCompletely destructive: most buildings are destroyed.
17866.1
Golfo di Patti earthquake
10 March 1786 · 47 km from here
IXDestructive: many buildings partly or fully collapse.
16985.7
Monti Iblei settentrionali earthquake
1 January 1698 · 46 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
16245.6
Monti Iblei settentrionali earthquake
3 October 1624 · 50 km from here
IXDestructive: many buildings partly or fully collapse.

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

The closest seismic structure

Gela-Catania

The epicentre lies about 11 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

1.6
2 km North-West of Ragalna
3 km South-West · 17 km
124 months ago
20 Apr, 02:44
1.4
3 km West of Ragalna
5 km South-West · 13 km
124 months ago
20 Apr, 03:25
1.5
2 km North-East of Ragalna
1 km South-East · 16 km
124 months ago
20 Apr, 07:28
1.5
3 km North-East of Ragalna
2 km East · 17 km
124 months ago
20 Apr, 08:09
1.3
123 months ago
24 Apr, 05:37
1.5
123 months ago
24 Apr, 05:51
2.0
3 km South-East of Riposto
23 km East · 1 km
124 months ago
15 Apr, 01:56
1.5
124 months ago
14 Apr, 02:56
2.4
1 km East of Giarre
19 km East · 6 km
123 months ago
27 Apr, 01:56
2.4
1 km East of Riposto
22 km East · 2 km
123 months ago
27 Apr, 19:49

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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