Vibrations and noise from blasting can travel long distances in the bedrock

Perceptible vibrations indoors can feel very unpleasant.

Mittamies työskentelee tunnelityömaalla.

Residents have reported objects moving on shelves and building structures making clicking sounds due to the vibrations caused by blasting. Citizens have felt vibrations in Alppila and the further reaches of Töölö. What is happening?

Maisa, our excavation expert, says the noise and vibration caused by blasting can travel long distances in the bedrock. People notice these noises and vibrations, especially if they are not part of the normal soundscape. People living near railways experience similar noises and vibrations from passing trains. Each individual has a different sensitivity to vibrations. Generally, people have a very low threshold for perceiving vibrations and find even small vibrations unpleasant indoors.

Seismic monitoring stations track seismological phenomena in Finland. The closest monitoring station is in Seurasaari. The blasting carried in the Laakso Hospital area is visible in Seurasaari and other surveying points, but the amplitudes are not particularly large.

The City of Helsinki regulates disruptive construction work

Blasting noise and vibrations annoy the neighbours, especially households with children or pets that are easily scared. 

The City must issue a permit before any disruptive work can begin. Among other things, the permit states the hours when noisy work is allowed. The Laakso construction site is subject to the same regulations as other corresponding work sites in central Helsinki. On average, the regulations are stricter in Helsinki than in other municipalities.

Vibration values are monitored constantly 

The Alliance prepared for the blasting work well before excavation began. The nearby properties were surveyed, and the blasting work was planned to avoid damaging the neighbouring buildings. 

During excavation, the vibrations are measured by seismometers placed in nearby real estate properties to monitor the amplitude of each blast. If a property does not have a seismometer, the vibration value is calculated using measurements from nearby meters.  As the work progresses, seismometers will be installed in the real estate properties affected by the work to track the amplitude of the vibrations.

The website shows the latest blasting hours and other working hours