All earthquakes
1.5
very light
EARTHQUAKE DETAILS

2 km North-East of Penna San Giovanni

116 months ago · 28 Nov, 09:16

A very light earthquake, probably not felt by people. At this depth the shaking is felt, but rarely causes damage.

Stronger than 68% of Italian events in the past year

Where

2 km North-East of Penna San GiovanniEarthquakes in the province of MacerataEarthquakes in Marche

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

61 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 ≈ 25 s

Animation sped up ~5× compared to reality.

  • Teramo
    51 km from the epicentre
    first tremor in ~10 s
    main shaking in ~16 s
  • Foligno
    52 km from the epicentre
    first tremor in ~10 s
    main shaking in ~17 s
  • Ancona
    57 km from the epicentre
    first tremor in ~11 s
    main shaking in ~18 s
  • Terni
    84 km from the epicentre
    first tremor in ~15 s
    main shaking in ~25 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

27 km
medium depth
3 times the height of Mount Everest

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

deeper than 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: 115 months ago the same area had a stronger quake (M3.5). This can only be said after the fact — it was not predictable beforehand.

3.5
The mainshock
3 km East of Ussita
115 months ago · 26 Dec, 20:56
Activity in the area right now (30 km radius)
2
last 24 hours
14
last 7 days
84
last 30 days
0 before2000 after
this quake
Strongest of the sequence3.5

How often does it happen here?

about every ~1 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 13020 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.

20166.6
Valnerina earthquake
30 October 2016 · 38 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
13286.5
Valnerina earthquake
1 December 1328 · 42 km from here
XCompletely destructive: most buildings are destroyed.
12796.2
Appennino umbro-marchigiano earthquake
30 April 1279 · 46 km from here
XCompletely destructive: most buildings are destroyed.
20166.2
Monti della Laga earthquake
24 August 2016 · 45 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

Southern Marche

The epicentre lies about 4 km from Southern Marche, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.9between 4 and 11 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

1.0
116 months ago
7 Dec, 11:52
1.0
4 km West of Valfornace
29 km West · 4 km
116 months ago
7 Dec, 12:04
0.9
116 months ago
7 Dec, 12:23
1.3
116 months ago
7 Dec, 12:43
1.9
4 km West of Valfornace
28 km West · 8 km
116 months ago
7 Dec, 12:45
1.5
116 months ago
7 Dec, 12:46
0.5
116 months ago
7 Dec, 12:53
2.0
116 months ago
7 Dec, 12:55
1.7
116 months ago
7 Dec, 12:55
1.1
116 months ago
7 Dec, 12:58

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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