# Urban Seismic Networks: A Worldwide Review  
[PERSON]  
1 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, 00143 Rome, Italy;[EMAIL_ADDRESS] (A.C.); [EMAIL_ADDRESS] (A.D.)1 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, 00143 Rome, Italy;[EMAIL_ADDRESS] (A.C.); [EMAIL_ADDRESS] (A.D.)1 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, 00143 Rome, Italy;[EMAIL_ADDRESS] (A.C.); [EMAIL_ADDRESS] (A.D.)1 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, 00143 Rome, Italy;[EMAIL_ADDRESS] (A.C.); [EMAIL_ADDRESS] (A.D.)1 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, 00143 Rome, Italy;[EMAIL_ADDRESS] (A.C.); [EMAIL_ADDRESS] (A.D.)1 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, 00143 Rome, Italy;[EMAIL_ADDRESS] (A.C.); [EMAIL_ADDRESS] (A.D.)1 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, 00143 Rome, Italy;[EMAIL_ADDRESS] (A.C.); [EMAIL_ADDRESS] (A.D.)1 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, 00143 Rome, Italy;[EMAIL_ADDRESS] (A.C.); [EMAIL_ADDRESS] (A.D.)1 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, 00143 Rome, Italy;[EMAIL_ADDRESS] (A.C.); [EMAIL_ADDRESS] (A.D.)1 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, 00143 Rome, Italy;[EMAIL_ADDRESS] (A.C.); [EMAIL_ADDRESS] (A.D.)1 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, 00143 Rome, Italy;[EMAIL_ADDRESS] (A.C.); [EMAIL_ADDRESS] (A.D.)1 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, 00143 Rome, Italy;[EMAIL_ADDRESS] (A.C.); [EMAIL_ADDRESS] (A.D.)1 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, 00143 Rome, Italy;[EMAIL_ADDRESS] (A.C.); [EMAIL_ADDRESS] (A.D.)1 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, 00143 Rome, Italy;[EMAIL_ADDRESS] (A.C.); [EMAIL_ADDRESS] (A.D.)1 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, 00143 Rome, Italy;[EMAIL_ADDRESS] (A.C.)1 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Nazionale Terremoti, 00143 Rome, Italy;antonio.  
phenomena, such as scientific studies, earthquake warning, and decision support systems. In this work, we refer to such infrastructure as \"Urban Seismic Networks\" (USN).  
The purposes of USNs is generally different than \"traditional\" country scale-networks. The latter typology is usually intended for earthquake observation and seismological studies on a broad scale. Although both types of networks can be integrated, each has its own characteristics and peculiarities while sharing the objective of earthquake risk reduction, as suggested by [PERSON] et al. (2019) [8]. In particular, urban-scale networks have distinct characteristics with respect to country-scale networks in terms of their coverage areas and density of nodes, which may even differ to some order of magnitude. The technical choices about the type of sensors and data transmission may differ as well.  
As the number of USNs, regardless the specific application, has been increasing over the last two decades, we recognize the importance of providing a complete picture on the topic of USNs, looking in particular at their design and at their technical characteristics and how these are related to the specific objectives of each urban network. For this purpose, we retrieved information on 105 USNs implemented worldwide. These networks' objectives and technical characteristics have been categorized to make for an easier synthesis.  
USNs represent crucial infrastructure because of the practical and scientific challenges they support, which is even more the case looking to the future perspective. This work can represent a reference and a practical guideline for future planners of urban networks.