All earthquakes
1.3
very light
EARTHQUAKE DETAILS

2 km South-East of Mazzarrone

1 month ago · 23 Jul, 21:45

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

Stronger than 55% of Italian events in the past year

Where

2 km South-East of MazzarroneEarthquakes in the province of CataniaEarthquakes 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

7 events
Magnitude:lightweakmoderatestrong

The energy released

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

1.3kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×355 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 ≈ 11 s

Animation sped up ~2× compared to reality.

  • Vittoria
    15 km from the epicentre
    first tremor in ~5 s
    main shaking in ~8 s
  • Ragusa
    19 km from the epicentre
    first tremor in ~5 s
    main shaking in ~9 s
  • Gela
    26 km from the epicentre
    first tremor in ~6 s
    main shaking in ~10 s
  • Modica
    29 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 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

23 km
medium depth
2.6 times the height of Mount Everest

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

in line with the area average (~20 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?

Aftershock

It is an aftershock: it follows a stronger quake (M1.9, 1 month ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

1.9
The mainshock
4 km East of San Michele di Ganzaria
1 month ago · 14 Jul, 19:14
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
3
last 30 days
3 before3 after
this quake
Strongest of the sequence1.9

How often does it happen here?

about every ~24 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 179 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.

16937.3
Sicilia sud-orientale earthquake
11 January 1693 · 39 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
15426.7
Sicilia sud-orientale earthquake
10 December 1542 · 36 km from here
XCompletely destructive: most buildings are destroyed.
11696.5
Sicilia sud-orientale earthquake
4 February 1169 · 37 km from here
XCompletely destructive: most buildings are destroyed.
16936.1
Sicilia sud-orientale earthquake
9 January 1693 · 41 km from here
VIII-IXDestructive: many buildings partly or fully collapse.

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

The closest seismic structure

Ragusa-Palagonia

The epicentre lies about 13 km from Ragusa-Palagonia, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.9between 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

1.5
27 days ago
29 Jul, 11:09
1.9
4 km East of San Michele di Ganzaria
26 km North-West · 32 km
1 month ago
14 Jul, 19:14
1.6
6 km East of Ragusa
22 km South-East · 25 km
21 days ago
4 Aug, 12:28
1.9
6 km East of Ragusa
22 km South-East · 27 km
21 days ago
4 Aug, 12:31
1.3
2 months ago
10 Jul, 10:32
1.5
6 km South-West of Mineo
25 km North · 27 km
2 months ago
2 Jul, 22:01

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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