All earthquakes
2.1
light
EARTHQUAKE DETAILS

1 km North of Pettorano sul Gizio

122 months ago · 26 Aug, 07:38

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

Stronger than 90% of Italian events in the past year

Where

1 km North of Pettorano sul GizioEarthquakes 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

33 events
Magnitude:lightweakmoderatestrong

The energy released

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

21kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×22 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 ≈ 19 s

Animation sped up ~3× compared to reality.

  • Chieti
    45 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • L'Aquila
    58 km from the epicentre
    first tremor in ~11 s
    main shaking in ~18 s
  • Pescara
    59 km from the epicentre
    first tremor in ~11 s
    main shaking in ~18 s
  • Montesilvano
    59 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 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

26 km
medium depth
2.9 times the height of Mount Everest

At this depth the shaking is felt, but rarely causes damage.

deeper 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: 121 months ago the same area had a stronger quake (M2.4). This can only be said after the fact — it was not predictable beforehand.

2.4
The mainshock
2 km South of Palena
121 months ago · 18 Sept, 14:31
Activity in the area right now (30 km radius)
1
last 24 hours
1
last 7 days
5
last 30 days
15 before17 after
this quake
Strongest of the sequence2.4

How often does it happen here?

about every ~11 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 374 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 · 35 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
17066.8
Maiella earthquake
3 November 1706 · 16 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 · 44 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

Barisciano-Sulmona

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

estimated maximum magnitude 7.0between 1 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

1.5
2 km South-West of Opi
25 km South-West · 10 km
122 months ago
23 Aug, 13:40
1.0
3 km West of Opi
25 km South-West · 9 km
122 months ago
21 Aug, 23:19
1.5
4 km North of Pescasseroli
20 km South-West · 10 km
122 months ago
31 Aug, 03:49
1.5
4 km West of Opi
25 km South-West · 11 km
122 months ago
19 Aug, 09:11
1.3
3 km West of Opi
24 km South-West · 9 km
122 months ago
19 Aug, 01:26
1.3
3 km West of Opi
25 km South-West · 11 km
122 months ago
2 Sept, 15:35
1.5
3 km South-East of Palena
16 km East · 15 km
122 months ago
3 Sept, 09:42
1.5
2 km West of Opi
25 km South-West · 10 km
122 months ago
16 Aug, 10:43
0.8
4 km South-West of Pescasseroli
27 km South-West · 12 km
122 months ago
16 Aug, 09:28
1.6
3 km West of Opi
25 km South-West · 10 km
122 months ago
15 Aug, 13:32

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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