All earthquakes
1.5
very light
EARTHQUAKE DETAILS

M1.5 earthquake · 4 km South-West of Lasa (BZ)

11 years ago · 28 Mar 2015, 19:15

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

Stronger than 69% of Italian events in the past year

Where

4 km South-West of LasaEarthquakes in the province of BolzanoEarthquakes in Trentino-Alto Adige

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

6 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 ≈ 36 s

Animation sped up ~7× compared to reality.

  • Bolzano
    56 km from the epicentre
    first tremor in ~10 s
    main shaking in ~16 s
  • Trento
    69 km from the epicentre
    first tremor in ~12 s
    main shaking in ~20 s
  • Brescia
    121 km from the epicentre
    first tremor in ~20 s
    main shaking in ~35 s
  • Bergamo
    124 km from the epicentre
    first tremor in ~21 s
    main shaking in ~36 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

12 km
medium depth
1.4 times the height of Mount Everest

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

in line with the area average (~10 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 (M1.8, 11 years ago) in the same area. Aftershocks are normal after an earthquake and tend to fade over time.

1.8
The mainshock
5 km West of Ultimo
11 years ago · 26 Mar 2015, 15:02
Activity in the area right now (30 km radius)
0
last 24 hours
3
last 7 days
14
last 30 days
4 before1 after
this quake
Strongest of the sequence1.8

How often does it happen here?

about every ~3 months

Within 50 km of this epicentre, a magnitude ≥ 2 earthquake has occurred on average this often: 45 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.

16225.4
Bassa Engadina, Ftan earthquake
3 August 1622 · 42 km from here
18275.0
Bassa Engadina, Ardez earthquake
2 April 1827 · 43 km from here
VIStrong: felt by everyone, many get scared; objects fall, first light damage to buildings.
19614.9
Val Monastero earthquake
9 August 1961 · 35 km from here
V-VIStrong: felt by everyone, many get scared; objects fall, first light damage to buildings.
20014.8
Val Venosta earthquake
17 July 2001 · 36 km from here
VIStrong: felt by everyone, many get scared; objects fall, first light damage to buildings.

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

The closest seismic structure

Giudicarie

The epicentre lies about 54 km from Giudicarie, one of the seismic structures mapped by INGV geologists.

estimated maximum magnitude 6.8between 5 and 12 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

1.8
5 km West of Ultimo
17 km East · 9 km
11 years ago
26 Mar 2015, 15:02
0.8
9 km North-West of Peio
15 km South · 10 km
11 years ago
4 Apr 2015, 19:06
1.6
5 km South of Tubre
15 km West · 8 km
11 years ago
14 Mar 2015, 00:10
1.1
5 km North-West of Malé
26 km South-East · 5 km
11 years ago
7 Mar 2015, 09:41
1.4
3 km South-East of Valdisotto
28 km South-West · 8 km
11 years ago
27 Feb 2015, 20:09

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).