Monitoring-Induced Seismicity in Urban Environment Using Low-Cost Stations: Lessons Learned from the Strasbourg Dense Semipermanent Seismic Network, France

Abstract With the growing number of geothermal energy projects near urban centers, monitoring seismicity in urban environments is becoming increasingly important. In recent years, the introduction of low-cost stations such as Raspberry Shake stations has provided a viable means of densifying seismic networks and enabling long-term monitoring in cities. However, their effectiveness compared to traditional stations remains to be assessed. In this study, we focus on the dense semipermanent seismic network (DSSN), which is primarily composed of Raspberry Shake stations and was deployed to monitor seismicity at the Vendenheim deep geothermal site near Strasbourg, France. Specifically, using the recorded noise at the stations, we evaluate the network’s ability to detect and locate local earthquakes. Our results show that detection and location performance vary significantly between day and night. These limitations can be mitigated either by complementing the DSSN with stations installed in quieter environments outside the urban area or by densifying the DSSN itself, up to a critical station density corresponding to a minimum interstation distance of about 2 km. In addition, we find that Raspberry Shake stations installed in private homes experience noise levels comparable to those of broadband stations located in public or commercial buildings. Our study shows that low-cost stations can contribute to high-resolution earthquake catalogs in urban environments alongside traditional stations. However, achieving consistent detection and location levels throughout the day can require high station density, careful site selection, and the inclusion of stations less affected by anthropogenic noise.