Das Erdbebenrisiko einer Megacity

The North Anatolian Fault Zone (NAFZ) in northwest Turkey, particularly the Marmara segment near Istanbul, represents a seismic gap that has remained inactive since 1766, posing a significant earthquake risk to the densely populated city of Istanbul with over 14 million residents. This study aimed to analyze the seismotectonic characteristics of the Marmara fault segment by implementing a local seismic network deployed offshore on the Princes Islands, known as the PIRES campaign, which is part of the GFZ Plate Boundary Initiative. The methodology involved recording microseismic events to characterize the fault system beneath the Sea of Marmara. Results revealed distinct seismically active zones suggesting that strain accumulation is partially released within the seismic gap. By integrating data from various seismic stations, refined fault plane solutions were obtained, enhancing our understanding of the fault’s behavior and structural features. The ongoing expansion of the PIRES network is expected to improve data resolution and facilitate comparative studies with other fault systems, such as the San Andreas Fault in California, thereby advancing the understanding of active tectonic processes in the region.