Description: Local-scale seismic networks within urbanized areas have been usually employed for short-living seismological experiments or studies. However the possibility, to install permanent (or long-term) earthquake monitoring networks within urban contexts began in the mid '90s.If, from one hand, this possibility was certainly boosted by the support coming from technological developments (digital devices for acquisition and transmission), from the other, the necessity was also driven by the recent global expansion of many urban centers into large metropolitan areas. Also the awareness of the seismic risk in urban center resulted in the increasing interest in the monitoring these areas, with particular focus the most exposed or the most vulnerable ones. Earthquake monitoring networks especially designed may reveal important tools for several tasks related to the seismic phenomena: from earthquake warnings, to emergency operational tasks during emergencies, or scientific studies. In this paper we refer to such earthquake networks as "Urban Seismic Networks" (USN).Because of the increasing resorting USNs for several applications, we consider useful to provide a comprehensive view of the state-of-the-art of the use of USNs, looking at their global distribution and objectives but, most of all, at their design and at their technical characteristics. We retrieved information about 71 USNs worldwide. The USN objectives, as well the other characteristics, have been classified into prearranged groups in order to provide to easily synthesize the various features of the USNs. This review will represent a reference and a guideline for future implementation of USNs.

Description: The Central Mediterranean is a geodynamically complex area resulting from the interaction between the European and African plates. This process caused strong lateral variation in lithospheric thickness and thus strong variation in the Moho topography.In this work we propose a new 3D Moho map for the Central Mediterranean, obtained from the interpolation of different data as: 2D velocity models (Scarascia et al., 1994; Chironi et al., 2000; Nicolich et al., 2000; Cassinis et al., 2005; Dellong et al., 2018; Agius et al., 2022), gravimetric profiles (Chironi et al., 2000; Dellong et al., 2018) and interpreted seismic reflection profile (Finetti et al., 2005; Civile et al., 2008; Catalano et al., 2013; Fedorik et al., 2018; Tugend et al., 2019; Sulli et al., 2021).In order to optimize the geometry of the Ionian slab, we used the hypocenters of the seismic events extrapolated from different databases. In particular, we collected relocated seismic events from 1981 to the present.We obtained a new constrained 3D Moho map for the Central Mediterranean that presents a strong lateral variation. Furthermore, the Ionian slab is quite different with respect to the model proposed by DISS (2021) and its geometry has been adapted to the hypocenters of the deepest seismic events (〉40 km deep). In particular it was verticalized starting from about 200 km depth and the width was changed depending on new available data.This model will allow a better understanding of the structure of the upper mantle and of the complex geodynamics of the area.

Description: In the framework H2020-ARCH project, an Urban Seismic Network (USN) based on MEMS accelerometers was implemented in and around the historic centre of Camerino. These sensors lend themselves to being installed in dense configurations in urban environments due to their low cost, moreover their lower performance is acceptable also given the high environmental noise generally recorded . The technology used to reduce costs and dimensions is MEMS, with the support of ARM processors for data storage operations locally and in remote servers. These accelerometer stations can be easily installed into the buildings or on footings in roadside cabinets. The innovation that we want to show with this work is the opportunity to use these systems to carry out measurable information for the characterization of the local site response. The historic centre of Camerino is located along a natural hill and has a high density of buildings of historical-cultural value, which suffered widespread damage during the 2016-2017 sequence of Central Italy. The accelerometric network allowed to record the Mw5.5 earthquake event of the sequence along the Unbro-Marche coast and other local events of lower intensity. These recordings, also combined with previous measurements of environment noise, made it possible to obtain information about local effects on different parts of the town centre.

Description: In the last decades each nation, especially those with high seismic risk, has up-graded its seismic network to keep it up with the state-of-the-art criteria. Here we perform the evaluation and a comparison between some the national seismic networks, to evaluate their coverage and their capabilities. We show example from Italy, Greece, Taiwan and New Zealand. For our analysis, we consider the spatial distribution of the nodes of the network together with the ancillary information related to the aims of the network itself (e.g. earthquakes’ distribution, seismic hazard, population, distribution on completeness magnitude). Such evaluation is performed with a statistical approach which includes descriptive spatial statistics in combination with point pattern techniques. We are able to highlight the strong points and the drawbacks for each of the considered earthquake monitoring network. Finally this approach helps in addressing future developments for the considered networks.