All earthquakes
1.0
very light
EARTHQUAKE DETAILS

2 km North-West of Rocca di Mezzo

6 months ago · 21 Feb, 18:18

A very light earthquake, probably not felt by people. At only a few km deep the shaking is felt more sharply at the surface.

Stronger than 30% of Italian events in the past year

Where

2 km North-West of Rocca di MezzoEarthquakes in the province of L'AquilaEarthquakes in Abruzzo

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

18 events
Magnitude:lightweakmoderatestrong

The energy released

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

0.5kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×1,000 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 ≈ 18 s

Animation sped up ~3× compared to reality.

  • L'Aquila
    11 km from the epicentre
    first tremor in ~2 s
    main shaking in ~4 s
  • Teramo
    53 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • Chieti
    57 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • Montesilvano
    63 km from the epicentre
    first tremor in ~11 s
    main shaking in ~18 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

8 km
shallow

At only a few km deep the shaking is felt more sharply at the surface.

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?

Foreshock

In hindsight it was a foreshock: 6 months ago the same area had a stronger quake (M1.8). This can only be said after the fact — it was not predictable beforehand.

1.8
The mainshock
4 km East of Avezzano
6 months ago · 5 Mar, 05:33
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
6
last 30 days
4 before13 after
this quake
Strongest of the sequence1.8

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: 2762 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.

19157.1
Marsica earthquake
13 January 1915 · 22 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17036.7
Aquilano earthquake
2 February 1703 · 29 km from here
XCompletely destructive: most buildings are destroyed.
14616.5
Aquilano earthquake
27 November 1461 · 12 km from here
XCompletely destructive: most buildings are destroyed.
20096.3
Aquilano earthquake
6 April 2009 · 11 km from here
IX-XCompletely destructive: most buildings are destroyed.

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

The closest seismic structure

Borbona-L'Aquila-Aremogna

The epicentre lies about 1 km from Borbona-L'Aquila-Aremogna, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.0between 2 and 14 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

1.4
6 months ago
28 Feb, 12:16
1.3
9 km South of Pizzoli
22 km North-West · 11 km
6 months ago
28 Feb, 22:36
1.8
4 km East of Avezzano
19 km South · 11 km
6 months ago
5 Mar, 05:33
1.6
5 km East of Avezzano
20 km South · 11 km
6 months ago
5 Mar, 05:43
1.5
5 km East of Avezzano
20 km South · 11 km
6 months ago
7 Mar, 07:46
1.3
5 km East of Avezzano
19 km South · 10 km
6 months ago
7 Mar, 09:13
1.4
7 km South-East of Pizzoli
24 km North · 10 km
6 months ago
7 Mar, 21:34
1.1
3 km West of Massa d'Albe
12 km South-West · 11 km
6 months ago
8 Mar, 11:28
1.1
4 km East of Avezzano
19 km South · 10 km
6 months ago
8 Mar, 13:47
1.8
3 km East of Tagliacozzo
22 km South-West · 10 km
7 months ago
2 Feb, 09:29

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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