All earthquakes
1.8
very light
EARTHQUAKE DETAILS

1 km North-East of Offida

138 months ago · 11 Feb, 15:29

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

Stronger than 82% of Italian events in the past year

Where

1 km North-East of OffidaEarthquakes 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

10 events
Magnitude:lightweakmoderatestrong

The energy released

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

7.6kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×63 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 ≈ 22 s

Animation sped up ~4× compared to reality.

  • Teramo
    31 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Montesilvano
    61 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Pescara
    67 km from the epicentre
    first tremor in ~12 s
    main shaking in ~20 s
  • Chieti
    74 km from the epicentre
    first tremor in ~13 s
    main shaking in ~22 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

25 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 (~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: 137 months ago the same area had a stronger quake (M3.4). This can only be said after the fact — it was not predictable beforehand.

3.4
The mainshock
14 km East of Grottammare
137 months ago · 2 Mar, 19:18
Activity in the area right now (30 km radius)
1
last 24 hours
3
last 7 days
7
last 30 days
6 before3 after
this quake
Strongest of the sequence3.4

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: 6580 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.

20166.2
Monti della Laga earthquake
24 August 2016 · 49 km from here
XCompletely destructive: most buildings are destroyed.
18735.8
Appennino marchigiano earthquake
12 March 1873 · 43 km from here
IXDestructive: many buildings partly or fully collapse.
19505.7
Gran Sasso earthquake
5 September 1950 · 49 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
19435.7
Ascolano earthquake
3 October 1943 · 9 km from here
IXDestructive: many buildings partly or fully collapse.

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

1.6
5 km North of Valle Castellana
27 km South-West · 25 km
138 months ago
6 Feb, 18:40
1.7
4 km East of Campli
24 km South · 25 km
139 months ago
29 Jan, 23:54
2.1
2 km East of Servigliano
23 km North-West · 22 km
139 months ago
29 Jan, 02:36
1.3
4 km South-West of Comunanza
30 km West · 10 km
139 months ago
28 Jan, 02:06
1.7
2 km West of Roccafluvione
29 km West · 23 km
138 months ago
26 Feb, 21:50
3.4
14 km East of Grottammare
25 km East · 8 km
137 months ago
2 Mar, 19:18
1.3
2 km South-East of Roccafluvione
26 km South-West · 11 km
139 months ago
22 Jan, 09:54
1.4
139 months ago
21 Jan, 04:15
1.6
2 km South of Roccafluvione
28 km South-West · 10 km
137 months ago
10 Mar, 01:32

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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