Measurements of earthquakes in both Denmark and Greenland have been available on the GEUS website for years as an automated table. Now, we are launching two new web portals making the data much more accessible and visual. Among other things, it will be clear how many tremors actually occur in both Denmark and Greenland. In Denmark, the vast majority of tremors are so small that they are not felt, but in Greenland the earthquakes are felt quite often.
Explore the new portals here:
What is shown on the maps?
The portals are based on interactive maps where all recorded tremors are visualised in near real time. This means, that the portals draw data directly from GEUS’ national earthquake database, where tremors are continuously registered and quality assured by our team of seismologists. This means, among other things, that non-seismic events – such as explosions from the military or other man-made tremors – are removed from the map. Furthermore, parameters such as time, epicenter and magnitude of the earthquake are adjusted as new calculations are made.
The data can be sorted so that, for example, only tremors of a certain magnitude or from a certain year are displayed. It is also possible to click on each of the earthquakes on the map and get more information on when it happened, at what depth and with what magnitude. The web portals also show seismological events measured in neighboring countries of both Denmark and Greenland. They are visible on both maps, but they are not quality assured, and therefore it is not possible to see whether or not they are actually earthquakes.
For the Danish web portal, measurements are dating back to 1930, i.e. almost 100 years. For Greenland the dataset goes back to 1969. When assessing data from early years, one can be led to believe that there were fewer earthquakes in the past. This is not the case, but is merely due to the fact that equipment and measurement efforts have greatly improved in the past century. Therefore, far more of the occurring tremors are detected today.
Freely available data
All earthquake data is made freely available in several standardised formats via the web portals. For instance:
- WMS and WFS services for Denmark and Greenland.
- A joint GeoJSON file, updated automatically for integration into the users’ own GIS systems.