Monitoring the Earth’s pulse

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When the earth trembles in Germany, it is normally only seismologists – earthquake researchers – who notice. It was something of an exception when furniture wobbled and cutlery in drawers jangled in a number of places in Northern Germany in late May 2016. Local measuring stations had registered two earthquakes of a magnitude of less than three – which is comparatively harmless. The earth shook the first time because layers of rock had shifted in a mining region, while the second quake was probably due to natural gas exploration activities.

A long tradition of seismic research

The map provides an overview of earthquake epicentres.

The danger posed by earthquakes is relatively small in Germany, yet there is a long tradition of conducting seismic research here. The first seismic measurement took place in Potsdam back in 1889 – of an earthquake that had occurred in far-away Japan. Since then, the city has evolved to become a hub for international earthquake and volcano research thanks to the Helmholtz Centre Potsdam – GFZ German Research Centre for Geosciences.

Researchers keen to better understand the causes of earthquakes

Earthquake reports from 350 measuring stations around the world are sent to the GFZ and made publicly accessible on the GEOFON Internet platform. The quakes that are registered are rarely entirely harmless. Generally the earth trembles because plates in the Earth’s crust move and rub up against one another. “We analyse the raw data showing the time sequence of the tremors so as to be able to precisely locate and describe the earthquakes”, explains Professor Frederik Tilmann, director of the Seismology Department. The more quakes that are observed, the easier it is to make statements about the structure of the Earth’s crust and about its movements. “If we better understand the structure, we can also better explain the causes of earthquakes”, says Tilmann.

A few seconds’ advance warning can save lives

Using this data and specially developed software, the geoscientists in Potsdam can generally pinpoint an earthquake’s geographic location and estimate its magnitude in less than a minute. “Even today, however, it is impossible to predict”, comments Frederik Tilmann. “Seismologists can only draw conclusions about the potential level of risk. Or, in the case of an earthquake that has already happened, they can give a warning before the most powerful tremors reach an at-risk city.” He explains that an advance warning of just half a minute or less can prevent more serious consequences, as this allows gas supply systems to be shut down or trains brought to a halt.

Research focused on Chile

The Potsdam geoscientists are taking a very close look at Chile – one of the regions with the highest earthquake risk in the world. When two tectonic plates collided off the country’s Pacific coast in September 2015, a quake with a magnitude of 8.3 was caused – a very powerful earthquake indeed. Cooperating with their colleagues at universities in Chile and France, the GFZ researchers operate a dense measurement network. Seismic measurements are combined with GPS data, among other things, with a view to monitoring gradual shifts. Geophysicists from the GEOMAR Helmholtz Centre for Ocean Research Kiel supplement this data with sonic measurements carried out in the deep sea. “We hope that this research will soon allow us to better understand the physics behind earthquakes so that we can determine whether there are any early warning signs that would indicate a serious earthquake”, says Tilmann.

Scientific findings alone are not enough

The methods employed by scientists are not enough to minimise the damage caused by natural disasters, however. After all, another important factor is how well people are prepared to deal with earthquakes. Do they know the safest place to seek refuge when an earthquake or tsunami strikes? Which building regulations are in force? How are risks communicated? So that methods can also be developed in order to allow protective strategies to be drawn up, the GFZ collaborates with economists and social scientists in the GEO.X network. In future, this research work could save many lives.