The man who keeps track of Sweden’s earthquakes
Researcher profile
Björn Lund keeps track of what’s happening on the screens of the Swedish National Seismic Network. A measuring station in Hälsingland is spiking and giving strange readings. Photo: Tobias Sterner.
He is often seen commenting on earthquakes and volcanic eruptions that have occurred somewhere across the globe. As Director of the Swedish National Seismic Network (SNSN), Björn Lund is able to monitor all kinds of movements in the Earth's crust in real time. More recently, attention has increasingly been directed at explosions and infrastructure sabotage that are also picked up by the instruments.
Björn Lund is monitoring the SNSN screens. At the moment things are very calm. Only one of the measuring stations is emitting a low-frequency, steady output. But this is not something that prompts a reaction from him.
“That’s interference,” he explains.
The measuring station is located in central Uppsala and the tremors are due to traffic noise and other human activity – not earthquakes.
Tsunami disaster led to permanent job
Since January 2003, he has been working with the SNSN, which is based at the Department of Earth Sciences. It started with a temporary post as an assistant professor. It could have been all over after that, but two years later the tsunami disaster struck. As a direct result, the government invested in SNSN and Björn Lund was offered a permanent position. Since 2018, he has been able to refer to himself as director. During his time here, a huge development has taken place.
“In 1998 we had six measuring stations on the Swedish network. One here and five scattered across Sweden. From 1998 to 2010 or so, it went from six to 60 measuring stations, which was a tremendous development. When I started here, we could barely see earthquakes smaller than magnitude three. We were lagging far behind in Sweden, but now we are at the forefront, especially in terms of automatic analysis. We have very strong coverage and good technology,” he adds.
Inside the workshop, Lund lifts up a seismometer that measures vibrations in the ground. Photo: Tobias Sterner.
The 2004 tsunami disaster
On Boxing Day 2004, a 9.3 magnitude earthquake struck west of the island of Sumatra in the Indian Ocean – the second strongest earthquake ever measured. The quake triggered tsunami waves up to 30 metres high that slammed into islands in the Bay of Bengal, coastal areas of Indonesia, Malaysia, Thailand, India, Sri Lanka and the Maldives. They claimed lives as far away as Somalia on the west coast of Africa, 500 miles from the earthquake’s epicentre. One reason for the high death toll was the lack of a tsunami monitoring and warning system – something which is now in place.
Read more: What happened next to the survivors of the tsunami disaster
Providing society with information and thus helping authorities and politicians make correct decisions is an important part of SNSN’s mission.
“I usually say that we have two main tasks; the scientific one where we collect data on earthquakes in Sweden, contribute to increasing knowledge about earthquakes and earthquake risks, but also the geological development: why and where we have earthquakes. The other side is the societal side, which of course also includes risk assessments,” explains Lund.
Two to three earthquakes daily in Sweden
As a researcher, he is mainly interested in Swedish earthquakes. On average, two to three earthquakes occur every day in Sweden, but the vast majority of them are too weak for us humans to feel them. They occur because the North American continental plate and the Eurasian plate, on which we are located, are drifting apart, causing stresses even far from the plate boundaries inside the plates.
However, the earthquakes can still puzzle scientists – like why they are so common in Hälsingland. In an ongoing research project, Lund and his colleagues are now looking for the explanation to that.
“There is a line of earthquakes that runs from Arbrå north of Bollnäs and then at a 45-degree angle to the coastline and out to sea north of Hudiksvall, but there is nothing to explain this in the geology. There are not even any good old deformation zones that would explain why they happen in this area. We now have 13 extra measuring stations there, partly to obtain data to see whether they are occurring on a common fracture system or some other reason why they are there,” continues Lund.
Part of the broken measuring station in Hälsingland has been repaired, and Lund and a technician will go there with it to make sure everything is working again. Photo: Tobias Sterner.
Protecting critical infrastructure is another area in which seismic measurements can be used. Together with Luleå University of Technology, Sunet (Swedish University Computer Network), the Swedish Transport Administration and LKAB, among others, Lund is working on a project that is partly about monitoring railways and land and undersea cables. The technology to be used is called DAS (Distributed Acoustic Sensing), which involves sending a laser pulse into a standard fibre optic cable for communication and then measuring the reflections of the laser pulse.
“The DAS technology makes it possible to use a standard communication cable for seismic measurements at intervals of just a few metres, and in cooperation with the Swedish Transport Administration we could therefore expand the seismic network in a fantastic way without having to build new measuring stations. It also allows us to measure ocean cables in areas where we have never been able to measure before, and can therefore provide us with completely new information about movements in the Earth’s crust. That is incredibly exciting,” says Lund.
Useful in police investigations involving blasts
More recently, SNSN’s sensitive equipment has also proved useful in police investigations involving blasts.
“It was so lucky that we were able to help even convict one of the criminals. We only had one station that picked up the blast. It was in Stockholm, and we had a measuring station in Bogesund which is quite close, only 11 kilometres from where the blast took place. We could say when the blast occurred, give or take half a second. And the police officers thought it was really cool that it could be determined so accurately,” says Lund.
Åsa Malmberg
Facts about Björn Lund
Born: Sundbyberg, outside Stockholm
Education: Master’s degree in Particle Physics from Uppsala University, Master's degree in Geophysics from Stanford, California, PhD in Seismology from Uppsala University in 2000.
On a free day, enjoys: Walking and skiing, and I used to be a rock climber.
If I hadn’t become a researcher: I was very keen to become a farmer when I was in my early teens.
Favourite travel destination: The Swedish mountains.
Hobby: Outdoor activities.
What inspires me: Meetings with positive, interested people.
What makes me happy: Being out in the woods, the outdoors.
What makes me angry: When people are unreasonable and do not listen to sensible arguments.
Latest book read: Nexus by Yuval Noah Harari
Facts about the tsunami:
On Boxing Day 2004, a 9.3 magnitude earthquake struck west of the island of Sumatra in the Indian Ocean – the second strongest earthquake ever measured. The quake triggered tsunami waves up to 30 metres high that slammed into islands in the Bay of Bengal, coastal areas of Indonesia, Malaysia, Thailand, India, Sri Lanka and the Maldives. They claimed lives as far away as Somalia on the west coast of Africa, 500 miles from the earthquake’s epicentre. One reason for the high death toll was the lack of a tsunami monitoring and warning system – something which is now in place.