All earthquakes
1.5
very light
EARTHQUAKE DETAILS

M1.5 earthquake · 4 km South-West of Balsorano (AQ)

10 years ago · 22 Sept 2016, 17:34

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

4 km South-West of BalsoranoEarthquakes 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

16 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 ≈ 20 s

Animation sped up ~4× compared to reality.

  • L'Aquila
    61 km from the epicentre
    first tremor in ~10 s
    main shaking in ~18 s
  • Velletri
    67 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Latina
    68 km from the epicentre
    first tremor in ~11 s
    main shaking in ~20 s
  • Tivoli
    69 km from the epicentre
    first tremor in ~12 s
    main shaking in ~20 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

10 km
shallow
1.1 times the height of Mount Everest

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?

Aftershock

It is an aftershock: it follows a stronger quake (M2.0, 10 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.0
The mainshock
5 km East of San Donato Val di Comino
10 years ago · 22 Sept 2016, 14:27
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
5
last 30 days
11 before4 after
this quake
Strongest of the sequence2.0

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: 350 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 · 28 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
13496.8
Lazio-Molise earthquake
9 September 1349 · 39 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
16546.3
Sorano earthquake
24 July 1654 · 18 km from here
XCompletely destructive: most buildings are destroyed.
19845.9
Monti della Meta earthquake
7 May 1984 · 43 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

Salto Lake-Ovindoli-Barrea

The epicentre lies about 12 km from Salto Lake-Ovindoli-Barrea, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.1between 1 and 15 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

2.0
10 years ago
22 Sept 2016, 14:27
1.3
4 km North of Settefrati
26 km East · 10 km
10 years ago
21 Sept 2016, 14:50
1.9
10 years ago
21 Sept 2016, 12:29
1.4
3 km North of Settefrati
25 km East · 10 km
10 years ago
21 Sept 2016, 06:19
0.6
4 km North of Settefrati
25 km East · 11 km
10 years ago
21 Sept 2016, 04:34
1.0
3 km North of Settefrati
25 km East · 11 km
10 years ago
18 Sept 2016, 12:12
1.2
2 km West of Opi
22 km East · 10 km
10 years ago
16 Sept 2016, 17:20
1.2
6 km South-East of Bisegna
24 km East · 17 km
10 years ago
29 Sept 2016, 16:36
1.0
10 years ago
7 Oct 2016, 21:20
1.1
4 km North of Pescasseroli
20 km East · 13 km
10 years ago
6 Sept 2016, 15:08

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).