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2.0
light
EARTHQUAKE DETAILS

M2.0 earthquake · 1 km North of San Roberto (RC)

11 years ago · 17 May 2015, 19:47

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

Stronger than 86% of Italian events in the past year

Where

1 km North of San RobertoEarthquakes in the province of Reggio CalabriaEarthquakes in Calabria

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

19 events
Magnitude:lightweakmoderatestrong

The energy released

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

15kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×32 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 ≈ 27 s

Animation sped up ~5× compared to reality.

  • Reggio di Calabria
    13 km from the epicentre
    first tremor in ~4 s
    main shaking in ~6 s
  • Messina
    24 km from the epicentre
    first tremor in ~5 s
    main shaking in ~9 s
  • Acireale
    84 km from the epicentre
    first tremor in ~14 s
    main shaking in ~25 s
  • Lamezia Terme
    94 km from the epicentre
    first tremor in ~16 s
    main shaking in ~27 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.

shallower than the area average (~42 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 (M2.9, 11 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.9
The mainshock
2 km North-East of Reggio di Calabria
11 years ago · 2 May 2015, 13:38
Activity in the area right now (30 km radius)
0
last 24 hours
3
last 7 days
15
last 30 days
9 before9 after
this quake
Strongest of the sequence2.9

How often does it happen here?

about every ~3 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 1323 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 · 11 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17837.1
Calabria meridionale earthquake
5 February 1783 · 19 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
18946.1
Calabria meridionale earthquake
16 November 1894 · 11 km from here
IXDestructive: many buildings partly or fully collapse.
19076.0
Aspromonte earthquake
23 October 1907 · 22 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

Aspromonte-Peloritani

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

estimated maximum magnitude 7.3between 2 and 13 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

1.7
4 km North of Roccaforte del Greco
14 km South-East · 19 km
11 years ago
16 May 2015, 07:26
1.9
4 km North-West of San Luca
19 km East · 17 km
11 years ago
11 May 2015, 06:42
2.3
11 years ago
28 May 2015, 11:41
2.2
11 years ago
30 May 2015, 11:36
1.7
4 km North-West of Samo
17 km South-East · 57 km
11 years ago
4 May 2015, 07:48
2.9
2 km North-East of Reggio di Calabria
11 km South-West · 66 km
11 years ago
2 May 2015, 13:38
1.6
11 years ago
7 Jun 2015, 07:35
1.4
4 km South-East of Scido
16 km East · 19 km
11 years ago
25 Apr 2015, 03:20
1.5
1 km East of Varapodio
23 km East · 11 km
11 years ago
24 Apr 2015, 21:10
1.8
11 years ago
24 Apr 2015, 13:53

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).