All earthquakes
1.8
very light
EARTHQUAKE DETAILS

2 km North of San Biase

105 months ago · 21 Jan, 03:56

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

2 km North of San BiaseEarthquakes in the province of CampobassoEarthquakes in Molise

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.

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 ≈ 23 s

Animation sped up ~4× compared to reality.

  • Benevento
    69 km from the epicentre
    first tremor in ~12 s
    main shaking in ~20 s
  • Caserta
    74 km from the epicentre
    first tremor in ~13 s
    main shaking in ~22 s
  • Chieti
    76 km from the epicentre
    first tremor in ~13 s
    main shaking in ~22 s
  • San Severo
    78 km from the epicentre
    first tremor in ~13 s
    main shaking in ~23 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

18 km
medium depth
2 times the height of Mount Everest

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

in line with the area average (~15 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 (M2.6, 106 months ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

2.6
The mainshock
2 km West of Vastogirardi
106 months ago · 26 Dec, 06:33
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
3
last 30 days
107 before52 after
this quake
Strongest of the sequence2.6

How often does it happen here?

about every ~8 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 526 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.

18056.7
Molise earthquake
26 July 1805 · 29 km from here
XCompletely destructive: most buildings are destroyed.
19845.9
Monti della Meta earthquake
7 May 1984 · 44 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.
12935.8
Sannio-Matese earthquake
4 September 1293 · 49 km from here
IXDestructive: many buildings partly or fully collapse.
20025.7
Molise earthquake
31 October 2002 · 27 km from here
VIII-IXDestructive: many buildings partly or fully collapse.

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

The closest seismic structure

Pescolanciano-Montagano

The epicentre lies about 8 km from Pescolanciano-Montagano, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.8between 11 and 25 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

1.2
3 km South-East of Carovilli
24 km West · 17 km
105 months ago
21 Jan, 06:33
1.5
2 km South of Vastogirardi
27 km West · 20 km
105 months ago
21 Jan, 13:03
1.6
2 km South of Vastogirardi
27 km West · 19 km
105 months ago
21 Jan, 13:03
2.1
105 months ago
21 Jan, 14:45
1.0
105 months ago
20 Jan, 15:53
1.6
105 months ago
21 Jan, 16:45
1.7
105 months ago
21 Jan, 17:37
1.8
105 months ago
21 Jan, 18:04
1.3
105 months ago
23 Jan, 09:49
1.5
2 km South of Vastogirardi
26 km West · 16 km
105 months ago
23 Jan, 09:54

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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