All earthquakes
2.8
light
EARTHQUAKE DETAILS

M2.8 earthquake · 2 km South-East of Salaparuta (TP)

8 years ago · 7 Apr 2018, 21:39

A light earthquake, rarely felt by people. At this depth the shaking is felt, but rarely causes damage.

Stronger than 97% of Italian events in the past yearThe strongest of the past 12 months within 50 km

Where

2 km South-East of SalaparutaEarthquakes in the province of TrapaniEarthquakes 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

11 events
Magnitude:lightweakmoderatestrong

The energy released

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

239kgof TNT equivalent
1.0 lightning bolt
M3
A magnitude 3 earthquake releases ×2 its energy
M2this quakeM4

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 ≈ 17 s

Animation sped up ~3× compared to reality.

  • Trapani
    46 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Marsala
    47 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Palermo
    51 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • Bagheria
    56 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 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

13 km
medium depth
1.4 times the height of Mount Everest

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

in line with the area average (~11 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?

Mainshock

It is the strongest quake of its sequence: so far it has been followed by 4 aftershocks within 30 km. Aftershocks tend to fade in number and strength over time.

Activity in the area right now (30 km radius)
1
last 24 hours
1
last 7 days
5
last 30 days
6 before4 after
this quake
Strongest of the sequence2.5

How often does it happen here?

about every ~5 months

Within 50 km of this epicentre, a magnitude ≥ 2.5 earthquake has occurred on average this often: 30 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.

19686.4
Valle del Belice earthquake
15 January 1968 · 1 km from here
XCompletely destructive: most buildings are destroyed.
19685.5
Valle del Belice earthquake
15 January 1968 · 7 km from here
19685.5
Valle del Belice earthquake
16 January 1968 · 11 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19685.4
Valle del Belice earthquake
15 January 1968 · 0 km from here
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

Mazara-Belice

The epicentre sits above this source area: the deep structure where this area's earthquakes can originate.

estimated maximum magnitude 6.1between 2 and 6 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

2.0
1 km South of Salaparuta
1 km West · 10 km
8 years ago
7 Apr 2018, 21:28
1.6
1 km South of Salaparuta
1 km West · 12 km
8 years ago
7 Apr 2018, 21:52
1.9
1 km South of Salaparuta
1 km West · 10 km
8 years ago
7 Apr 2018, 21:23
1.6
1 km South-East of Salaparuta
1 km North-West · 10 km
8 years ago
7 Apr 2018, 22:40
1.3
8 years ago
7 Apr 2018, 18:53
1.8
0 km East of Salaparuta
1 km North-West · 10 km
8 years ago
7 Apr 2018, 18:15
2.5
8 years ago
7 Apr 2018, 17:07
1.5
2 km South-East of Salaparuta
0 km North-East · 12 km
8 years ago
10 Apr 2018, 20:53
1.3
1 km South-East of Salemi
16 km West · 20 km
8 years ago
26 Apr 2018, 21:41
1.4
5 km West of Menfi
17 km South-West · 11 km
8 years ago
14 Mar 2018, 00:38

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).