All earthquakes
1.3
very light
EARTHQUAKE DETAILS

2 km South-East of Appignano del Tronto

101 months ago · 21 Feb, 02:07

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

Stronger than 54% of Italian events in the past year

Where

2 km South-East of Appignano del TrontoEarthquakes in the province of Ascoli PicenoEarthquakes 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.

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 ≈ 21 s

Animation sped up ~4× compared to reality.

  • Teramo
    25 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Montesilvano
    59 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Pescara
    65 km from the epicentre
    first tremor in ~12 s
    main shaking in ~20 s
  • L'Aquila
    69 km from the epicentre
    first tremor in ~12 s
    main shaking in ~21 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: 100 months ago the same area had a stronger quake (M3.0). This can only be said after the fact — it was not predictable beforehand.

3.0
The mainshock
3 km North-East of Valle Castellana
100 months ago · 14 Mar, 07:42
Activity in the area right now (30 km radius)
0
last 24 hours
3
last 7 days
9
last 30 days
21 before45 after
this quake
Strongest of the sequence3.0

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: 11991 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 · 46 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
16396.2
Monti della Laga earthquake
7 October 1639 · 43 km from here
XCompletely destructive: most buildings are destroyed.
20166.2
Monti della Laga earthquake
24 August 2016 · 41 km from here
XCompletely destructive: most buildings are destroyed.
20166.1
Valnerina earthquake
26 October 2016 · 47 km from here

Source: Parametric Catalogue of Italian Earthquakes CPTI15 (INGV, CC BY 4.0).

The closest seismic structure

Southern Marche

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

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

1.7
3 km South of Roccafluvione
22 km West · 21 km
101 months ago
21 Feb, 00:54
1.3
2 km West of Torricella Sicura
24 km South · 16 km
101 months ago
20 Feb, 07:57
1.6
8 km South of Acquasanta Terme
30 km South-West · 14 km
101 months ago
19 Feb, 14:42
0.9
3 km South-East of Roccafluvione
19 km South-West · 13 km
101 months ago
16 Feb, 13:24
1.0
2 km South-West of Acquasanta Terme
26 km South-West · 16 km
101 months ago
28 Feb, 17:09
0.7
4 km South of Acquasanta Terme
27 km South-West · 15 km
101 months ago
28 Feb, 23:42
1.3
5 km South-West of Acquasanta Terme
29 km South-West · 15 km
101 months ago
1 Mar, 00:09
0.9
1 km East of Montegallo
26 km West · 22 km
101 months ago
13 Feb, 00:56
1.4
3 km West of Torricella Sicura
25 km South-West · 15 km
101 months ago
1 Mar, 08:45
1.4
3 km East of Venarotta
11 km West · 19 km
101 months ago
3 Mar, 04:03

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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