30 years of seismicity in the south-western Alps and northern Apennines as recorded by the Regional Seismic Network of northwestern Italy

The aim of this work is to describe the seismicity of the South-western Alps and Northern Apennines from the very detailed picture provided by thirty years of operation of the Regional Seismic Network of northwestern Italy .PublishedTeatro Metastasio - Palazzo Vaj, Prato, Italy1.1. TTC - Monitoraggio sismico del territorio nazionaleope

Reliability of the automatic procedures for locating earthquakes in southwestern Alps and northern Apennines (Italy)

International audienceReliable automatic procedure for locating earthquake in quasi-real time is strongly needed for seismic warning system, earthquake preparedness, and producing shaking maps. The reliability of an automatic location algorithm is influenced by several factors such as errors in picking seismic phases, network geometry, and velocity model uncertainties. The main purpose of this work is to investigate the performances of different automatic procedures to choose the most suitable one to be applied for the quasi-real-time earthquake locations in northwestern Italy. The reliability of two automatic-picking algorithms (one based on the Characteristic Function (CF) analysis, CF picker, and the other one based on the Akaike's information criterion (AIC), AIC picker) and two location methods (“Hypoellipse” and “NonLinLoc” codes) is analysed by comparing the automatically determined hypocentral coordinates with reference ones. Reference locations are computed by the “Hypoellipse” code considering manually revised data and tested using quarry blasts. The comparison is made on a dataset composed by 575 seismic events for the period 2000–2007 as recorded by the Regional Seismic network of Northwestern Italy. For P phases, similar results, in terms of both amount of detected picks and magnitude of travel time differences with respect to manual picks, are obtained applying the AIC and the CF picker; on the contrary, for S phases, the AIC picker seems to provide a significant greater number of readings than the CF picker. Furthermore, the “NonLinLoc” software (applied to a 3D velocity model) is proved to be more reliable than the “Hypoellipse” code (applied to layered 1D velocity models), leading to more reliable automatic locations also when outliers (wrong picks) are present

Automatic P- and S-wave local earthquake tomography: testing performance of the automatic phase-picker engine "RSNI-Picker"

In this work, we test a fully automatic procedure to obtain local earthquake tomography (LET), starting from seismic waveforms and applying the capability of the automatic phase picker and locator engine \u201cRSNI-Picker\u201d (Spallarossa et al., 2014), which is based on a multistep iterative procedure working on P and S arrival times. This code is currently operating as part of the Earthquake Monitoring System at the University of Genoa (RSNI designates the regional seismic network of northwestern Italy). In particular, we compare P- and S-wave tomographic results obtained using this fully automatic procedure for picking and locations with those based on data from accurate manual picking and revised locations. We use a dataset of 409 earthquakes that occurred in the Trentino region (Northeastern Italy) in the 1994\u20132007 period. The highly variable waveform qualities (e.g., signal-tonoise ratio), mainly due to recording stations equipped with different types of sensors and digitizers (including both one-component narrowband stations and three-component broadband seismic stations), ensure a severe test for the automatic procedure. The comparison of the two 3D velocity propagation models for the Trentino region (i.e., LET images) from the automatic and manual procedures, shows maximum differences of 0.54 and 0:34 km=s for P and S waves, respectively (if we consider 90% of all the computed absolute velocities, as a reference percentage). The automatic LET shows velocity anomaly distributions and reliability patterns (e.g., resolution diagonal element [RDE] values) similar to those obtained using the manual procedure; 90% of RDE differences are lower than 0.15. The results obtained by testing the RSNI-Picker engine suggest it can be used to automatically process large amounts of seismic recordings in order to identify P and S wavepicks for reliable LET analysis

Epidemiology and Clinical-Demographic Characteristics of Suicide Attempts in Alcohol Use Disorders in an Italian Population

Suicide is a leading cause of morbidity worldwide. Among the known risk factors, alcohol use disorders (AUDs) are particularly relevant, but data on the epidemiology and characteristics of suicide attempts (SA) in this group are lacking. We used electronic health records of national health services to identify individuals who received a diagnosis of AUD in the Metropolitan area of Bologna from 2009 to 2019. In this cohort we identified accesses to Emergency Departments for SA from 2009 to 2020. The Crude Suicide Rate (CSR) for 1,000 Person Years was 2.93, higher than the general population. The CSR was higher in females, within one year from receiving the diagnosis of AUD, in patients with psychiatric comorbidities, concomitant abuse of cannabis or benzodiazepines. As for Covid-19 pandemic, the risk ratio of SA was significantly higher in 2020 compared to 2019 in females. Our results are relevant to identify clinical risk factors for SA in patients with AUDs, which are strongly associated with suicide risk but with scarce data in the previous literature and paucity of evidence-based therapeutic interventions

Seismicity of Northwestern Italy during the last 30 years

The aim of this work is to describe the seismicity of Northwestern Italy from the very detailed picture provided by 30 years of accurate instrumental recordings coming from the Regional Seismic Network of Northwestern Italy (RSNI\u2014University of Genoa). In an attempt to provide, for the first time, a comprehensive view of the seismicity in the area, this study describes the main characteristics of the database collected by the RSNI network. The seismicity is spread almost over the entire area, but it is mainly concentrated in the Northern Apennines and in the western sector of the Alps. The seismicity of the area is superficial: It is almost confined to the first 20 km of depth. Only a few deeper events are located in a small area southwest of the city of Turin, down to a depth of 80 km, and below the Northern Apennines down to 60\u201370-km depth. The majority of the earthquakes in this sector of the Italian peninsula are of low magnitude; nevertheless, the areas where the highest magnitude earthquakes took place during the last three decades are the Northern Apennines and the lower Piedmont, on land, and the Ligurian Sea, offshore. They are indeed the areas where the most damaging historical earthquakes have occurred, giving emphasis, if necessary, to the importance of continuous seismic monitoring

30 years of seismicity in the south-western Alps and northern Apennines as recorded by the Regional Seismic Network of northwestern Italy

The aim of this work is to describe the seismicity of the South-western Alps and Northern Apennines from the very detailed picture provided by thirty years of operation of the Regional Seismic Network of northwestern Italy