All earthquakes
1.9
very light
EARTHQUAKE DETAILS

9 km East of Portopalo di Capo Passero

38 months ago · 4 Jul, 08:40

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

Stronger than 85% of Italian events in the past year

Where

9 km East of Portopalo di Capo PasseroEarthquakes in the province of SiracusaEarthquakes 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

2 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 ≈ 22 s

Animation sped up ~4× compared to reality.

  • Siracusa
    37 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Modica
    43 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • Ragusa
    56 km from the epicentre
    first tremor in ~10 s
    main shaking in ~18 s
  • Vittoria
    72 km from the epicentre
    first tremor in ~13 s
    main shaking in ~22 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

28 km
medium depth
3.2 times the height of Mount Everest

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

deeper than 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?

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
0
last 30 days
0 before1 after
this quake
Strongest of the sequence1.6

How often does it happen here?

about every ~28 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 154 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.

11255.8
Siracusa earthquake
7 June 1125 · 44 km from here
VIII-IXDestructive: many buildings partly or fully collapse.
17274.6
Val di Noto earthquake
7 January 1727 · 31 km from here
VII-VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
16934.6
Modica earthquake
23 February 1693 · 46 km from here
VIStrong: felt by everyone, many get scared; objects fall, first light damage to buildings.
16934.6
Modica earthquake
12 May 1693 · 46 km from here
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

Scicli-Giarratana

The epicentre lies about 46 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
3 km South-West of Avola
28 km North-West · 19 km
38 months ago
23 Jul, 16:07

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).

We use cookies to analyse site traffic and improve your experience.

Privacy PolicyCookie Policy