All earthquakes
1.5
very light
EARTHQUAKE DETAILS

M1.5 earthquake · 3 km West of Cansano (AQ)

10 years ago · 20 Dec 2015, 06:39

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 69% of Italian events in the past year

Where

3 km West of CansanoEarthquakes 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

25 events
Magnitude:lightweakmoderatestrong

The energy released

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

2.7kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×178 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 ≈ 17 s

Animation sped up ~3× compared to reality.

  • Chieti
    43 km from the epicentre
    first tremor in ~7 s
    main shaking in ~13 s
  • Pescara
    57 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • Montesilvano
    58 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • L'Aquila
    60 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

7 km
shallow

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

shallower than 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: 10 years ago the same area had a stronger quake (M2.2). This can only be said after the fact — it was not predictable beforehand.

2.2
The mainshock
3 km North-East of Rivisondoli
10 years ago · 17 Jan 2016, 15:33
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
10
last 30 days
16 before8 after
this quake
Strongest of the sequence2.2

How often does it happen here?

about every ~12 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 368 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 · 39 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17066.8
Maiella earthquake
3 November 1706 · 13 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
13496.8
Lazio-Molise earthquake
9 September 1349 · 47 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
16546.3
Sorano earthquake
24 July 1654 · 46 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

Deep Abruzzo Citeriore Basal Thrust

The epicentre lies about 3 km from Deep Abruzzo Citeriore Basal Thrust, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.5between 8 and 18 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

1.3
2 km North-East of Villavallelonga
30 km South-West · 11 km
10 years ago
18 Dec 2015, 13:57
1.2
2 km North-East of Villavallelonga
30 km South-West · 11 km
10 years ago
22 Dec 2015, 01:02
1.4
3 km North-East of Rocca Pia
6 km South-East · 5 km
10 years ago
18 Dec 2015, 06:17
1.4
10 years ago
18 Dec 2015, 01:45
1.7
4 km North-East of Rocca Pia
6 km South-East · 7 km
10 years ago
17 Dec 2015, 06:49
1.4
2 km South of Scontrone
27 km South · 16 km
10 years ago
25 Dec 2015, 12:34
1.8
2 km South of San Pietro Avellana
27 km South-East · 20 km
10 years ago
25 Dec 2015, 19:32
1.4
10 years ago
27 Dec 2015, 02:42
1.2
2 km North-West of Pescocostanzo
7 km South-East · 8 km
10 years ago
12 Dec 2015, 01:53
1.4
4 km North-East of Rocca Pia
6 km South-East · 4 km
10 years ago
11 Dec 2015, 01:41

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).