All earthquakes
1.2
very light
EARTHQUAKE DETAILS

M1.2 earthquake · 3 km East of Torremaggiore (FG)

9 years ago · 11 Oct 2017, 04:48

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 48% of Italian events in the past year

Where

3 km East of TorremaggioreEarthquakes in the province of FoggiaEarthquakes in Puglia

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

3 events
Magnitude:lightweakmoderatestrong

The energy released

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

1.0kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×501 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.

  • San Severo
    21 km from the epicentre
    first tremor in ~4 s
    main shaking in ~7 s
  • Foggia
    37 km from the epicentre
    first tremor in ~6 s
    main shaking in ~11 s
  • Manfredonia
    47 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Cerignola
    65 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

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

shallower than 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 (M1.6, 9 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

1.6
The mainshock
9 km South-East of San Paolo di Civitate
9 years ago · 4 Oct 2017, 00:02
Activity in the area right now (30 km radius)
0
last 24 hours
0
last 7 days
4
last 30 days
1 before1 after
this quake
Strongest of the sequence1.6

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: 511 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.

16276.7
Capitanata earthquake
30 July 1627 · 13 km from here
XCompletely destructive: most buildings are destroyed.
16276.0
Capitanata earthquake
7 August 1627 · 14 km from here
IXDestructive: many buildings partly or fully collapse.
16576.0
Capitanata earthquake
29 January 1657 · 15 km from here
IX-XCompletely destructive: most buildings are destroyed.
18755.9
Gargano earthquake
6 December 1875 · 35 km from here
VIIIRuinous: partial collapses in ordinary buildings, widespread heavy damage.

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

The closest seismic structure

Ripabottoni-San Severo

The epicentre lies about 5 km from Ripabottoni-San Severo, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.1between 6 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

1.4
8 years ago
17 Oct 2017, 17:19
1.6
9 years ago
4 Oct 2017, 00:02

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).