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  • 1
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    Stream2segment: An Open‐Source Tool for Downloading, Processing, and Visualizing Massive Event‐Based Seismic Waveform Datasets (2019)
    Seismological Society of America (SSA)
    Details
    Publication Date: 2019
    Description: 〈span〉〈div〉ABSTRACT〈/div〉The task of downloading comprehensive datasets of event‐based seismic waveforms has been made easier through the development of standardized webservices but is still highly nontrivial because the likelihood of temporary network failures or subtle data errors naturally increases when the amount of requested data is in the order of millions of relatively short segments. This is even more challenging because the typical workflow is not restricted to a single massive download but consists of fetching all possible available input data (e.g., with several repeated download executions) for a processing stage producing any desired user‐defined output. Here, we present stream2segment, a highly customizable Python 2+3 package helping the user in the entire workflow of downloading, inspecting, and processing event‐based seismic data by means of a relational database management system as archiving storage, which has clear performance and usability advantages, and an integrated processing subroutine requiring a configuration file and a single Python function to produce user‐defined output. Stream2segment can also produce diagnostic maps or user‐defined plots, which, unlike existing tools, do not require external software dependencies and are not static images but instead are interactive browser‐based applications ideally suited for data inspection or annotation tasks and subsequent training of classifiers in foreseen supervised machine‐learning applications.Stream2segment has already been used as a data quality tool for datasets within the European Integrated Data Archive and to create a weak‐motion database (in the form of a so‐called flat file) for the stable continental region of Europe in the context of the European Ground Shaking Intensity Model service, in turn an important building block for seismic hazard studies.〈/span〉
    Print ISSN: 0895-0695
    Electronic ISSN: 1938-2057
    Topics: Geosciences
    Published by Seismological Society of America (SSA)
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  • 2
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    Harmonized local magnitude attenuation function for Europe using the European Integrated Data Archive (EIDA) (2019)
    Oxford University Press
    Details
    Publication Date: 2019
    Description: 〈span〉〈div〉SUMMARY〈/div〉We derive a harmonized local magnitude scale across Europe using data disseminated by network operators through the European Integrated Data Archive (EIDA). We first calibrate simultaneously a set of non-parametric attenuation functions regionalized by considering six different regions covering central and southern Europe, anchoring the models to the Richter’s scale at 17 km. Uncertainties on the attenuation coefficients, station corrections and magnitude values are evaluated through bootstrap analysis. The obtained attenuation functions show significant differences among the regions, up to 0.4 m.u. at 400 km, being the attenuation of the Wood–Anderson amplitude stronger for regions in the Mediterranean area. The non-parametric attenuation functions capture the changes in the rate of attenuation with distance due to the effects of later arrivals generated by crustal heterogeneity. A second calibration is performed to derive a parametric attenuation model. We consider a piece-wise linear function to describe the attenuation with the logarithm of distance, introducing two breakpoint distances at 10 and 60 km. For distances above 10 km, we also consider the anelastic attenuation term. We apply a mixed effect regression with network-dependent random effects on the anelastic coefficients. The parametric analysis confirms the stronger attenuation for networks operating in the Mediterranean area, such as the Italian and Greek networks, with respect to networks located in continental Europe. The network-dependent random effects allow us to quantify the between-network variability for different networks operating in the same region or country. The observed between-network variability is within ±0.2 m.u., smaller than the variability among the six regions.〈/span〉
    Print ISSN: 2051-1965
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 3
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    Capturing Regional Variations of Hard‐Rock Attenuation in Europe (2019)
    Seismological Society of America (SSA)
    Details
    Publication Date: 2019
    Description: 〈span〉〈div〉Abstract〈/div〉A proper assessment of seismic reference site conditions has important applications as they represent the basis on which ground motions and amplifications are generally computed. Besides accounting for the average 〈span〉S〈/span〉‐wave velocity over the uppermost 30 m (VS30), the parameterization of high‐frequency ground motions beyond source‐corner frequency received significant attention. κ, an empirical parameter introduced by 〈a href="https://pubs.geoscienceworld.org/bssa#rf5"〉Anderson and Hough (1984)〈/a〉, is often used to represent the spectral decay of the acceleration spectrum at high frequencies. The lack of hard‐rock records and the poor understanding of the physics of κ introduced significant epistemic uncertainty in the final seismic hazard of recent projects. Thus, determining precise and accurate regional hard‐rock κ0 values is critical. We propose an alternative procedure for capturing the reference κ0 on regional scales by linking the well‐known high‐frequency attenuation parameter κ and the properties of multiple‐scattered coda waves. Using geological and geophysical data around more than 1300 stations for separating reference and soft soil sites and based on more than 10,000 crustal earthquake recordings, we observe that κ0 from multiple‐scattered coda waves seems to be independent of the soil type but correlated with the hard‐rock κ0, showing significant regional variations across Europe. The values range between 0.004 s for northern Europe and 0.020 s for the southern and southeastern parts. On the other hand, measuring κ (and correspondingly κ0) on the 〈span〉S〈/span〉‐wave window (as classically proposed), the results are strongly affected by transmitted (reflected, refracted, and scattered) waves included in the analyzed window biasing the proper assessment of κ0. This effect is more pronounced for soft soil sites. In this way, κ0coda can serve as a proxy for the regional hard‐rock κ0 at the reference sites.〈/span〉
    Print ISSN: 0037-1106
    Electronic ISSN: 1943-3573
    Topics: Geosciences , Physics
    Published by Seismological Society of America (SSA)
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  • 4
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    Harmonized local magnitude attenuation function for Europe using the European Integrated Data Archive (EIDA) (2019)
    Oxford University Press
    Details
    Publication Date: 2019
    Description: 〈span〉〈div〉Summary〈/div〉We derive a harmonized local magnitude scale across Europe using data disseminated by network operators through the European Integrated Data Archive (EIDA). We first calibrate simultaneously a set of non-parametric attenuation functions regionalized by considering six different regions covering central and southern Europe, anchoring the models to the Richter’s scale at 17 km. Uncertainties on the attenuation coefficients, station corrections and magnitude values are evaluated through bootstrap analysis. The obtained attenuation functions show significant differences among the regions, up to 0.4 m.u. at 400 km, being the attenuation of the Wood-Anderson amplitude stronger for regions in the Mediterranean area. The non-parametric attenuation functions capture the changes in the rate of attenuation with distance due to the effects of later arrivals generated by crustal heterogeneity. A second calibration is performed to derive a parametric attenuation model. We consider a piece-wise linear function to describe the attenuation with the logarithm of distance, introducing two breakpoint distances at 10 and 60 km. For distances above 10km, we also consider the anelastic attenuation term. We apply a mixed effect regression with network-dependent random effects on the anelastic coefficients. The parametric analysis confirms the stronger attenuation for networks operating in the Mediterranean area, such as the Italian and Greek networks, with respect to networks located in continental Europe. The network-dependent random effects allow us to quantify the between-network variability for different networks operating in the same region or country. The observed between-network variability is within ±0.2 m.u., smaller than the variability among the six regions.〈/span〉
    Print ISSN: 2051-1965
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 5
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    Stream2segment: An Open‐Source Tool for Downloading, Processing, and Visualizing Massive Event‐Based Seismic Waveform Datasets (2019)
    Seismological Society of America (SSA)
    Details
    Publication Date: 2019
    Description: 〈span〉〈div〉ABSTRACT〈/div〉The task of downloading comprehensive datasets of event‐based seismic waveforms has been made easier through the development of standardized webservices but is still highly nontrivial because the likelihood of temporary network failures or subtle data errors naturally increases when the amount of requested data is in the order of millions of relatively short segments. This is even more challenging because the typical workflow is not restricted to a single massive download but consists of fetching all possible available input data (e.g., with several repeated download executions) for a processing stage producing any desired user‐defined output. Here, we present stream2segment, a highly customizable Python 2+3 package helping the user in the entire workflow of downloading, inspecting, and processing event‐based seismic data by means of a relational database management system as archiving storage, which has clear performance and usability advantages, and an integrated processing subroutine requiring a configuration file and a single Python function to produce user‐defined output. Stream2segment can also produce diagnostic maps or user‐defined plots, which, unlike existing tools, do not require external software dependencies and are not static images but instead are interactive browser‐based applications ideally suited for data inspection or annotation tasks and subsequent training of classifiers in foreseen supervised machine‐learning applications.Stream2segment has already been used as a data quality tool for datasets within the European Integrated Data Archive and to create a weak‐motion database (in the form of a so‐called flat file) for the stable continental region of Europe in the context of the European Ground Shaking Intensity Model service, in turn an important building block for seismic hazard studies.〈/span〉
    Print ISSN: 0895-0695
    Electronic ISSN: 1938-2057
    Topics: Geosciences
    Published by Seismological Society of America (SSA)
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  • 6
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    Harmonized local magnitude attenuation function for Europe using the European Integrated Data Archive (EIDA) (2019)
    Oxford University Press
    Details
    Publication Date: 2019-04-13
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Royal Astronomical Society.
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  • 7
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    Splitting parameter yield (SPY): A program for semiautomatic analysis of shear wave splitting (2012)
    Elsevier
    Details
    Publication Date: 2017-04-03
    Description: SPY is a Matlab algorithm that analyzes seismic waveforms in a semiautomatic way, providing estimates of the two observables of the anisotropy: the shear-wave splitting parameters. We chose to exploit those computational processes that require less intervention by the user, gaining objectivity and reliability as a result. The algorithm joins the covariance matrix and the cross-correlation techniques, and all the computation steps are interspersed by several automatic checks intended to verify the reliability of the yields. The resulting semiautomation generates two new advantages in the field of anisotropy studies: handling a huge amount of data at the same time, and comparing different yields. From this perspective, SPY has been developed in the Matlab environment, which is widespread, versatile, and user-friendly. Our intention is to provide the scientific community with a new monitoring tool for tracking the temporal variations of the crustal stress field.
    Description: Published
    Description: 138-145
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: restricted
    Keywords: Crustal anisotropy ; Waveform analysis ; Seismic monitoring ; Stress field ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 8
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    GEOFON Annual Report 2017 (2019)
    GFZ German Research Centre for Geosciences
    In:  Scientific Technical Report STR
    Details
    Publication Date: 2020-08-10
    Description: The GEOFON program consists of a global seismic network (GE Network), a seismological data centre (GEOFON DC) and a global earthquake monitoring system (GEOFON EQinfo). These three pillars are part of the MESI research infrastructure of the Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences aiming at facilitating scientific research. GEOFON provides real-time seismic data, access to its own and third party data from the archive facilities as well as global and rapid earthquake information. The GEOFON Seismological Software can be considered a fourth cross-cutting module of the GEOFON Program. Data, services, products and software openly distributed by GEOFON are used by hundreds of scientists and data centres worldwide. Its earthquake information service is accessed directly by tens of thousands of visitors. The SeisComP software package is the flagship software provided to the community, which is geared for seismic observatory and data centre needs and used extensively to support our internal operations. Like all other MESI (Modular Earth Science Infrastructure) modules GEOFON has the majority of users outside the GFZ as well as an external advisory committee that provides advice to the GFZ Executive Board and to the GEOFON team. This report describes the main activities carried out within the three GEOFON pillars and the software development group.
    Language: English
    Type: info:eu-repo/semantics/report
    Format: application/pdf
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  • 9
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    The European Ground Shaking Intensity Model (EGSIM) Service: Current Status and Future Developments (2018)
    In:  Book of Abstracts
    Details
    Publication Date: 2020-02-12
    Type: info:eu-repo/semantics/conferenceObject
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  • 10
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    Supervised machine learning approaches to faciliate seismological data intensive applications (2016)
    In:  Tagungsband
    Details
    Publication Date: 2020-02-12
    Type: info:eu-repo/semantics/conferenceObject
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