Luzi, Lucia

The behaviour of the ground surface and of structures subjected to earthquakes can be estimated analysing the accelerograms of seismic records. The ground motion is strongly dependent on several factors and the ability to record, characterize and extract the main features of waveforms is essential to better understand these dependencies. One of the most difficult steps of this analysis is the waveforms’ processing. Its purpose is the estimation and the removal of noise in the records, to evaluate reliable ground motion. In this framework a processing tool fully integrated within the Engineering Strong Motion (ESM) database was designed [Paolucci et al., 2011; Luzi et al., 2016]. In the last decade the number of waveforms is sharply increased and so is the time it takes to process them. To solve this issue a possible solution is to broaden the number of qualified people involved in the processing. The main aim of this tutorial is to teach the largest number of people how to use the ESM processing tool and to provide some important guidelines for the thresholds of the parameters to set. In the text a step by step processing routine is depicted with a description of the purpose for each parameter. In addition, a suite of explanatory examples with peculiar situations is given.

The determination of ground motion is crucial to plan the appropriate emergency activities, especially in areas characterised by an intense seismic history like the Italian peninsula. Ground motion assessment is generally based on the seismological parameters reported in the instrumental and parametric seismic catalogues. Therefore, the computation of shaking scenarios of historical earthquakes is very challenging, due to the poorly constrained variables (i.e., magnitudes, epicentral location, seismogenic sources), derived from the macroseismic intensity. In this study, we propose a novel approach to investigate the location and parametrization of the seismogenic sources of historical earthquakes and derive shaking scenarios. To this aim, the ground motion of two historical events, the Fabriano (1741, Mw = 6.1, Imax IX MCS) and Camerino (1799, Mw = 6.1, Imax IX–X MCS) earthquakes is simulated. In order to include the site response, a Vs,30 map of the Umbria and Marche regions is created from near-surface data. Different causative faults solutions are tested, finally discussing the ideal seismogenic source based on the residual analysis between observed and simulated macroseismic intensities. The resultant shaking scenarios of the two events are obtained by integrating observed intensities and simulations.

The strategy for data processing in the Engineering Strong-Motion Database (ESM) is to disseminate only manually revised data to ensure the highest quality. However, manual processing is no longer sustainable, due to the ever-increasing rate of digital earth-quake records, from global, regional, and national seismic networks, and a new frame-work for strong-motion data processing is required, so that records are automatically processed and the human revision is restricted to selected significant records. To this end, we present ESMpro—a modular Python software for a renewed processing frame-work of ESM. The software is available in a stand-alone beta version to facilitate testing and sharing among the scientific community. ESMpro provides automatic settings for waveform trimming and filtering, along with the automatic recognition of poor-quality data and multiple events. ESMpro allows classifying each record in different quality classes to reduce manual revision on a subset of the incoming data. ESMpro also allows handling different processing techniques in a modular and flexible structure to facilitate the implementation of new or alternative algorithms and file formats. The testing performed on the ESM database results in a good correspondence between the automatic and manual data processing, supporting the migration toward fully automatic procedures for massive data processing.

The main objective of this work is to provide two zonations of Italy useful to incorporate regional source and path effects in empirical Ground Motion Models (GMMs). To this end, we revise existing zonations developed for seismic and tsunami hazard studies, based on the results of a residual analysis between the observations of the ITACAext dataset and the predictions of ITA18, a GMM recently developed for Italy. The analysis consists in the decomposition of the residuals into repeatable terms, according to the well-established approach used for the calibration of non-ergodic models. Based on the spatial trend of the interpolated residuals, and geological and seismological considerations, the zonations are proposed and discussed, in the perspective of supporting regionalization of a future generation of GMMs for Italy.

In this study, we exploit the advantages of non-ergodic modelling of the ground motion to map the regional characteristics of source and propagation effects in Italy. In particular, we focused on the study of source and propagation effects obtained from the decomposition of the total residuals, i.e. the logarithmic difference of ITACAext observations and the model predictions, for active crustal earthquakes in Italy. The spatial trends, obtained from interpolating the residuals, clearly showed areas where the motion was significantly different from that predicted by the reference model, and in particular was underestimated. This is the case, for example, for many events with epicentres in northern Italy and the southern Ionian Sea. In addition, the study shows that paths across the Po Valley and the Adriatic coast are characterised by slower attenuation compared to that observed in the central Apennines. In addition, a marked difference between attenuation in the volcanic domain of Etna and the Hyblaean Mountains is clearly observed.

Strong-motion records and open access to strong-motion data repositories are fundamental to seismology, earthquake engineering and practice. The main archive to disseminate high quality processed waveforms for the European-Mediterranean region is the Engineering Strong-Motion Database (ESM, https://esm-db.eu). ESM is developed under the general coordination of the ORFEUS Strong-Motion Management Committee (Observatories and Research facilities for European Seismology; http://orfeus-eu.org/), with the aim to provide users daily access to updated strong-motion waveforms of earthquakes with magnitude greater than 4, mainly recorded in the Pan-European regions. ESM is fully compatible with the European Integrated Data Archive (EIDA; http://orfeus-eu.org/data/eida/) and disseminates waveforms and related metadata according to the Federation of Digital Seismograph Networks (FDSN, https://www.fdsn.org/networks/). The strategy of ESM is to disseminate only manually processed data to ensure the highest quality. However, the rapid increase in the number of waveforms, due to the increment of seismic stations, leads to the need of automatic procedures for data processing and data quality control. In this work, we present ESMpro, a modular Python software for a renewed processing framework of ESM. The ESM data processing is improved with: (1) automated data quality-check that speeds up the processing time through the rejection of poor-quality records; (2) advancement of the automatic settings for waveform trimming and filtering; (3) introduction of different algorithms for data processing (Paolucci et al., 2011; Schiappapietra et al., 2021); (4) modular and flexible software structure that allows the addition of new algorithms and custom workflows. The accuracy of the updated automatic processing is evaluated by comparison with the waveforms processed by expert analysts, used as benchmarks (Mascandola et al., 2022). ESMpro is distributed in a stand-alone Beta version available on GitLab (D’Amico et al., 2022; https://shake.mi.ingv.it/esmpro/), following the Open Science principles to promote collaborations and contributions from the scientific community. In the next future, a renewed ESM web-processing frontend will be developed to include the ESMpro improvements, as well as new functionalities to process stand-alone data (i.e., not stored in the ESM database) and to allow different input seismic data formats. How to cite: Mascandola, C., D'Amico, M., Russo, E., Luzi, L., Lanzano, G., Felicetta, C., Pacor, F., and Sgobba, S.: Toward a renewed data processing of the Engineering Strong Motion (ESM) database, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-2210, https://doi.org/10.5194/egusphere-egu23-2210, 2023.

In this paper, we present the work carried out to characterize the spatial variability of seismic site response related to local soil conditions in the city of Milan and its surroundings, an area with ~3 million inhabitants and a high density of industrial facilities. The area is located at the northwestern end of the Po Plain, a large and deep sedimentary basin in northern Italy. An urban-scale seismo-stratigraphic model is developed based on new passive and active seismic data, supported by the available geological data and stratigraphic information from shallow and deep vertical wells. In particular, 33 single-station and 4 ambient-vibration array measurements are acquired, together with 4 active multichannel analyses of surface waves (MAWS). To estimate the resonant frequencies of the sediments, the horizontal to vertical spectral ratio technique (HVSR) is applied to the ambient-vibration recordings, whereas to determine the Rayleighwave dispersion curves from the passive array, the data are analysed using the conventional frequency-wavenumber, the modified spatial autocorrelation and the extended spatial autocorrelation (ESAC) techniques. The array data are used to determine the local shear wave velocity profiles, VS, via joint inversion of the Rayleighwave dispersion and ellipticity curves deduced from the HVSR. The results from HVSR show three main bands of amplified frequencies, the first in the range 0.17–0.23 Hz, the second from 0.45 to 0.65 Hz and the third from 3 to 8 Hz. A decreasing trend of the main peaks is observed from the northern to the southern part of the city, allowing us to hypothesize a progressive deepening of the relative regional chrono-stratigraphic unconformities. The passive ambient noise array and MASW highlight the dispersion of the fundamental mode of the Rayleigh-wave in the range 0.4–30 Hz, enabling to obtain detailed Vs. profiles with depth down to about 1.8 km. The seismo-stratigraphic model is used as input for 1D numerical modelling assuming linear soil conditions. The theoretical 1D transfer functions are compared to the HVSR curves evaluated from both ambient noise signals and earthquake waveforms recorded by the IV. MILN station in the last 10 years.

Correction to: Bulletin of Earthquake Engineering https://doi.org/10.1007/s10518-021-01077-1

The growing interest in the open access of ground­motion data, web­services, and tools motivate every year a new release of the ITalian ACcelerometric Archive (ITACA), which represents the most complete collection of accelerometric waveforms recorded in Italy. In the last years, ITACA has undergone an important renewal process resulting in a new layout of the website (http:/itaca.mi.ingv.it) and substantial changes in the database content and services. In this work we present the main feature of the last release of ITACA v3.1 (last accessed on July 2020), providing Users with information to browse the website and to access and analyze data.

Strong ground motion records and free open access to strong‐motion data repositories are fundamental inputs to seismology, engineering seismology, soil dynamics, and earthquake engineering science and practice. This article presents the current status and outlook of the Observatories and Research Facilities for European Seismology (ORFEUS) coordinated strong‐motion seismology services, namely the rapid raw strong‐motion (RRSM) and the engineering strong‐motion (ESM) databases and associated web interfaces and webservices. We compare and discuss the role and use of these two systems using the Mw 6.5 Norcia (Central Italy) earthquake that occurred on 30 October 2016 as an example of a well‐recorded earthquake that triggered major interest in the seismological and earthquake engineering communities. The RRSM is a fully automated system for rapid dissemination of earthquake shaking information, whereas the ESM provides quality‐checked, manually processed waveforms and reviewed earthquake information. The RRSM uses only data from the European Integrated Waveform Data Archive, whereas the ESM also includes offline data from other sources, such as the ITalian ACcelerometric Archive (ITACA). Advanced software tools are also included in the ESM to allow users to process strong‐motion data and to select ground‐motion waveform sets for seismic structural analyses. The RRSM and ESM are complementary services designed for a variety of possible stakeholders, ranging from scientists to the educated general public. The RRSM and ESM are developed, organized, and reviewed by selected members of the seismological community in Europe, including strong‐motion data providers and expert users. Global access and usage of the data is encouraged. The ESM is presently the reference database for harmonized seismic hazard and risk studies in Europe. ORFEUS strong‐motion data are open, “Findable, Accessible, Interoperable, and Reusable,” and accompanied by licensing information. The users are encouraged to properly cite the data providers, using the digital object identifiers of the seismic networks.