All earthquakes
1.5
very light
EARTHQUAKE DETAILS

M1.5 earthquake · 1 km North of Sassofeltrio (PU)

10 years ago · 11 Nov 2015, 20:18

A very light earthquake, probably not felt by people. Being deep, it is felt less at the surface.

Stronger than 69% of Italian events in the past year

Where

1 km North of SassofeltrioEarthquakes in the province of Pesaro e UrbinoEarthquakes 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

17 events
Magnitude:lightweakmoderatestrong

The energy released

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

2.7kgof TNT equivalent
Less than the energy of a lightning bolt
M3
A magnitude 3 earthquake releases ×178 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 ≈ 16 s

Animation sped up ~3× compared to reality.

  • Rimini
    15 km from the epicentre
    first tremor in ~7 s
    main shaking in ~12 s
  • Pesaro
    26 km from the epicentre
    first tremor in ~8 s
    main shaking in ~13 s
  • Cesena
    32 km from the epicentre
    first tremor in ~8 s
    main shaking in ~14 s
  • Fano
    39 km from the epicentre
    first tremor in ~9 s
    main shaking in ~16 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

39 km
deep
4.4 times the height of Mount Everest

Being deep, it is felt less at the surface.

deeper than the area average (~12 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 (M3.5, 10 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

3.5
The mainshock
2 km South-West of Montescudo-Monte Colombo
10 years ago · 11 Nov 2015, 19:13
Activity in the area right now (30 km radius)
0
last 24 hours
2
last 7 days
7
last 30 days
10 before6 after
this quake
Strongest of the sequence3.5

How often does it happen here?

about every ~9 days

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 486 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.

17816.5
Cagliese earthquake
3 June 1781 · 34 km from here
XCompletely destructive: most buildings are destroyed.
13896.0
Alta Valtiberina earthquake
18 October 1389 · 45 km from here
IXDestructive: many buildings partly or fully collapse.
17686.0
Appennino forlivese earthquake
19 October 1768 · 49 km from here
IXDestructive: many buildings partly or fully collapse.
15846.0
Appennino forlivese earthquake
10 September 1584 · 42 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

Riminese onshore

The epicentre lies about 4 km from Riminese onshore, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 7.0between 2 and 10 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

3.5
10 years ago
11 Nov 2015, 19:13
0.9
1 km West of Montecopiolo
14 km West · 19 km
10 years ago
11 Nov 2015, 18:05
1.3
10 years ago
11 Nov 2015, 11:42
0.7
2 km North of Urbania
26 km South · 9 km
10 years ago
12 Nov 2015, 08:11
0.9
10 years ago
11 Nov 2015, 08:10
1.0
10 years ago
11 Nov 2015, 05:40
0.8
10 years ago
11 Nov 2015, 03:18
1.2
4 km South-West of San Leo
12 km West · 18 km
10 years ago
11 Nov 2015, 00:01
0.9
6 km North-East of Urbania
25 km South · 10 km
10 years ago
13 Nov 2015, 08:16
1.4
10 years ago
14 Nov 2015, 04:45

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).