All earthquakes
2.1
light
EARTHQUAKE DETAILS

M2.1 offshore earthquake

3 years ago · 20 Aug 2023, 02:59

A light earthquake, rarely felt by people. Being deep, it is felt less at the surface.

Stronger than 90% of Italian events in the past year

Where

Nearest Italian town: Ricadi (VV)Earthquakes in the province of Vibo ValentiaEarthquakes in Calabria

Epicentre at sea

The epicentre is at sea: for the same magnitude, the shaking is felt less on land, because the energy fades along the way before reaching the coast.

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

23 events
Magnitude:lightweakmoderatestrong

The energy released

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

21kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×22 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 ≈ 53 s

Animation sped up ~10× compared to reality.

  • Messina
    40 km from the epicentre
    first tremor in ~26 s
    main shaking in ~45 s
  • Reggio di Calabria
    55 km from the epicentre
    first tremor in ~27 s
    main shaking in ~46 s
  • Lamezia Terme
    86 km from the epicentre
    first tremor in ~29 s
    main shaking in ~50 s
  • Acireale
    105 km from the epicentre
    first tremor in ~31 s
    main shaking in ~53 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

151 km
deep
17 times the height of Mount Everest

Being deep, it is felt less at the surface.

deeper than the area average (~79 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 (M3.6, 3 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

3.6
The mainshock
Tirreno Meridionale [Mare]
3 years ago · 27 Jul 2023, 22:07
Activity in the area right now (30 km radius)
0
last 24 hours
6
last 7 days
20
last 30 days
14 before8 after
this quake
Strongest of the sequence3.6

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: 1797 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.

19087.1
Stretto di Messina earthquake
28 December 1908 · 49 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
18946.1
Calabria meridionale earthquake
16 November 1894 · 47 km from here
IXDestructive: many buildings partly or fully collapse.
19786.0
Golfo di Patti earthquake
15 April 1978 · 37 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19285.9
Calabria centro-meridionale earthquake
7 March 1928 · 45 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

Bagnara-Bovalino

The epicentre lies about 23 km from Bagnara-Bovalino, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.1between 3 and 12 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

2.2
3 years ago
19 Aug 2023, 22:04
2.5
3 years ago
16 Aug 2023, 09:33
2.0
Tirreno Meridionale [Mare]
14 km North-East · 159 km
3 years ago
14 Aug 2023, 19:32
2.0
Tirreno Meridionale [Mare]
11 km South-East · 132 km
3 years ago
26 Aug 2023, 08:09
3.1
3 years ago
26 Aug 2023, 21:53
2.2
22 km North of Milazzo
20 km South-West · 132 km
3 years ago
12 Aug 2023, 15:31
1.5
3 years ago
3 Sept 2023, 20:20
2.5
23 km North-West of Ricadi
29 km North-East · 162 km
3 years ago
2 Aug 2023, 08:33
2.9
23 km West of Ricadi
17 km North-East · 163 km
3 years ago
31 Jul 2023, 21:09
2.0
Tirreno Meridionale [Mare]
8 km South-West · 157 km
3 years ago
31 Jul 2023, 14:13

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).