Acoustic events on a small seismological network – shock waves from thunder and fireballs

Th e Geological Survey of Denmark and Greenland (GEUS) operates a network of seismic stations in Denmark primarily to detect earthquakes. But from time to time other sources than earthquakes generate seismic signals that are detected at the stations. Here we show that both meteoroids and thunder have generated seismic signals with high signal-to-noise ratios at some of GEUS’ seismic stations (Fig. 1). Th e purpose of the seismic stations is to provide data for the earthquake database of the Kingdom of Denmark, hosted and maintained by GEUS. In order to avoid that the earthquake database is contaminated by other events not related to tectonism, these events are given special markers when possible.