All earthquakes
1.3
very light
EARTHQUAKE DETAILS

M1.3 earthquake · 2 km North of Fontecchio (AQ)

11 years ago · 23 Apr 2015, 05:14

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 55% of Italian events in the past year

Where

2 km North of FontecchioEarthquakes 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

22 events
Magnitude:lightweakmoderatestrong

The energy released

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

1.3kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×355 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 ≈ 15 s

Animation sped up ~3× compared to reality.

  • L'Aquila
    19 km from the epicentre
    first tremor in ~3 s
    main shaking in ~6 s
  • Chieti
    45 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Teramo
    47 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Montesilvano
    51 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 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 (~12 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: 11 years 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 South-East of Massa d'Albe
11 years ago · 7 May 2015, 10:40
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
9
last 30 days
11 before10 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: 2480 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 · 27 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17066.8
Maiella earthquake
3 November 1706 · 43 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17036.7
Aquilano earthquake
2 February 1703 · 34 km from here
XCompletely destructive: most buildings are destroyed.
14616.5
Aquilano earthquake
27 November 1461 · 9 km from here
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 sits above this source area: the deep structure where this area's earthquakes can originate.

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

1.6
11 years ago
24 Apr 2015, 14:23
1.7
11 years ago
25 Apr 2015, 06:42
1.5
11 years ago
20 Apr 2015, 12:26
1.6
11 years ago
14 Apr 2015, 19:04
1.7
6 km West of Pietracamela
27 km North-West · 11 km
11 years ago
12 Apr 2015, 22:55
1.3
1 km West of L'Aquila
20 km West · 11 km
11 years ago
4 May 2015, 03:18
0.7
3 km South-West of L'Aquila
20 km West · 10 km
11 years ago
4 May 2015, 03:33
0.8
6 km West of Pietracamela
29 km North-West · 14 km
11 years ago
11 Apr 2015, 02:24
1.5
2 km North-East of Fossa
12 km North-West · 17 km
11 years ago
9 Apr 2015, 13:38
1.8
4 km South-East of Massa d'Albe
22 km South-West · 10 km
11 years ago
7 May 2015, 10:40

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).