20th century Felt Earthquakes in Belgium

How many earthquakes were experienced in your municipality?

In 2024, the Seismology and Gravimetry section of the Royal Observatory of Belgium (ROB) published a new paper presenting an overview of a century of felt earthquakes in Belgium. Compiling the seismic impact on Belgium was rendered possible by reviewing all testimonies of the Belgian population to the ROB on how they experienced various earthquakes throughout a century. The paper is freely available to the public and the data can be consulted online.

This new work, entitled ‘The Belgian traditional macroseismic (BTM) database of the twentieth century’ published in the Journal of Seismology, results from the PhD research of Ben Neefs, a PhD funded entirely by a ROB PhD grant.

Since its origin, the ROB is responsible for detecting and measuring earthquakes on the Belgian territory. Prior to the existence of a modern seismic network, the people’s reports on how they experienced an earthquake were the only information on the impact of an event. The intensity of shaking can be derived from these reports, an important parameter called macroseismic intensity, which allows demonstrating the impact of an earthquake to the public and the authorities.

The applied survey practices to gather this macroseismic intensity data, however, evolved significantly over the twentieth century: from small-scale ad hoc improvised surveys to the mass distribution of collective questionnaire versions sent to local authorities. We thoroughly re-evaluated the original source material to create the Belgian Traditional Macroseismic (BTM) database, a comprehensive compilation of 20th-century macroseismic data in which all sources are properly referenced.

The BTM database currently consists of 23,950 intensity data points (IDPs) on the European Macroseismic Scale for 80 felt earthquakes in and around Belgium, ranging from 2.4 to 5.8 on the local magnitude (M_L) scale. Each IDP is provided with a source type and each earthquake is attributed a data quality parameter that indicates the level of uncertainty associated with its IDP source quality.

The open publication of the BTM database:

• facilitates the use of Belgian macroseismic data for a variety of seismological purposes
• summarizes the overall seismic impact on Belgium for the duration of a century
• allows the Belgian population to consult these data:
  • How many earthquakes were felt in your municipality in the twentieth century?
  • Which earthquake had the largest impact on your municipality?
  • What was the largest magnitude of an event in your region?

We invite you to read our work…

Neefs, B., Van Noten, K., Vanneste, K. et al. The Belgian traditional macroseismic (BTM) database of the twentieth century. J Seismol (2024). https://doi.org/10.1007/s10950-024-10266-9

… and to explore the data following the link below (data shared under a CC BY 4.0 license). You can browse through all the earthquakes, or find the overview per municipality:

Neefs B, Van Noten K, Vanneste K, Camelbeeck T (2024) The Belgian Traditional Macroseismic (BTM) Database of the 20th century: online database. Royal Observatory of Belgium. https://doi.org/10.24414/2b5w-j029