There is scientific consensus that an earthquake of a magnitude of at least 7 will soon occur on the North Anatolian Fault, which runs south of İstanbul. This earthquake would render one-fifth of İstanbul’s buildings uninhabitable, which means that approximately 200,000 buildings would be expected to suffer moderate or severe damage. As a part of preparedness for the anticipated earthquake, people in İstanbul are invited to have their buildings risk tested. This article, pivoting on cultural anthropology and science and technology studies, investigates how earthquake-proneness of buildings in İstanbul is technically and legally examined and determined. It ethnographically analyzes the risk assessments and demonstrates that the risk is enacted differently through distinctive engineering practices and legal regulations in different networks. When the two different risk assessment processes are examined in İstanbul, a building that is categorized as risky due to its earthquake vulnerability could be regarded as sturdy in the other assessment.