All earthquakes
1.4
very light
EARTHQUAKE DETAILS

M1.4 earthquake · 1 km West of Spinete (CB)

11 years ago · 2 Aug 2015, 14:27

A very light earthquake, probably not felt by people. At only a few km deep the shaking is felt more sharply at the surface.

Stronger than 63% of Italian events in the past year

Where

1 km West of SpineteEarthquakes 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

10 events
Magnitude:lightweakmoderatestrong

The energy released

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

1.9kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×251 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 ≈ 19 s

Animation sped up ~4× compared to reality.

  • Caserta
    50 km from the epicentre
    first tremor in ~8 s
    main shaking in ~15 s
  • Benevento
    51 km from the epicentre
    first tremor in ~9 s
    main shaking in ~15 s
  • Acerra
    64 km from the epicentre
    first tremor in ~11 s
    main shaking in ~19 s
  • Aversa
    67 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

9 km
shallow
1 times the height of Mount Everest

At only a few km deep the shaking is felt more sharply at the surface.

in line with the area average (~14 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: 11 years ago the same area had a stronger quake (M2.3). This can only be said after the fact — it was not predictable beforehand.

2.3
The mainshock
3 km South-West of Gildone
11 years ago · 18 Aug 2015, 05:52
Activity in the area right now (30 km radius)
3
last 24 hours
10
last 7 days
12
last 30 days
5 before4 after
this quake
Strongest of the sequence2.3

How often does it happen here?

about every ~7 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 574 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.

14567.2
Appennino centro-meridionale earthquake
5 December 1456 · 33 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
16887.1
Sannio earthquake
5 June 1688 · 30 km from here
XICatastrophic: very few buildings remain standing; landslides and ground cracks.
13496.8
Lazio-Molise earthquake
9 September 1349 · 45 km from here
X-XICatastrophic: very few buildings remain standing; landslides and ground cracks.
18056.7
Molise earthquake
26 July 1805 · 5 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

Miranda-Apice

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

estimated maximum magnitude 6.9between 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

1.0
11 years ago
2 Aug 2015, 16:07
1.2
11 years ago
31 Jul 2015, 00:17
1.1
2 km South of Baranello
9 km East · 8 km
11 years ago
24 Jul 2015, 21:27
1.4
2 km West of Cercemaggiore
23 km East · 14 km
11 years ago
17 Aug 2015, 20:54
2.3
3 km South-West of Gildone
22 km East · 17 km
11 years ago
18 Aug 2015, 05:52
1.1
2 km South-West of Isernia
24 km West · 22 km
11 years ago
17 Jul 2015, 11:40
1.0
1 km East of Pesche
17 km West · 11 km
11 years ago
11 Jul 2015, 19:04
0.9
3 km East of Busso
10 km East · 16 km
11 years ago
3 Jul 2015, 21:56
0.9
2 km West of Civitanova del Sannio
17 km North-West · 11 km
11 years ago
1 Sept 2015, 12:04

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).