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  • 1
    Publication Date: 2019-06-18
    Description: 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 S‐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 Anderson and Hough (1984), 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 S‐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.
    Print ISSN: 0037-1106
    Electronic ISSN: 1943-3573
    Topics: Geosciences , Physics
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  • 2
  • 3
    Publication Date: 2020-12-08
    Description: We investigate the dependence of event-specific ground-motion residuals in the Ridgecrest region, California. We focus on the impact of using either local (ML) or moment (Mw) magnitude, for describing the source scaling of a regional ground-motion model. To analyze homogeneous Mw, we compute the source spectra of about 2000 earthquakes in the magnitude range 2.5–7.1, by performing a nonparametric spectral decomposition. Seismic moments and corner frequencies are derived from the best-fit ω−2 source models, and stress drop is computed assuming standard circular rupture model. The Brune stress drop varies between 0.62 and 24.63 MPa (with median equal to 3.0 MPa), and values for Mw〉5 are mostly distributed above the 90th percentile. The median scaled energy for Mw
    Print ISSN: 0037-1106
    Electronic ISSN: 1943-3573
    Topics: Geosciences , Physics
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  • 4
    Publication Date: 2012-03-01
    Print ISSN: 0098-3004
    Electronic ISSN: 1873-7803
    Topics: Geosciences , Computer Science
    Published by Elsevier
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  • 5
    Publication Date: 2023-07-03
    Description: Abstract
    Description: The Early-Warning and Rapid Impact Assessment with real-time GNSS in the Mediterranean (EWRICA) is a federal Ministry of Education and Research funded project (funding period: 2020-2023) that aims to develop fast kinematic and point source inversion and modeling tools combining GNSS-based near field data with traditional broadband ground velocity and accelerometer data. Fast and robust estimates of seismic source parameters are essential for reliable hazard estimates, e.g. in the frame of tsunami early warning. Hence, EWRICA aims for the development and testing of new real time seismic source inversion techniques based on local surface displacements. The resulting methods shall be applied for tsunami early warning purposes in the Mediterranean area. In this framework, this repository is a suite of four packages that can be used and combined in different ways and are ewricacore, ewricasiria, ewricagm and ewricawebapp. These four packages can be deployed in a docker container (see instructions below) to demonstrate a possible output of Early-Warning and Rapid Impact Assessment. In the Docker, a probabilistic earthquake source inversion report (ewricasiria) and a Neural network based Shake map (ewricagm) are generated for two past earthquakes whose data (event and waveform) is continuously served by GEOFON servers at regualr intervals to produce and test a real case scenario. The whole workflow is managed by ewricacore, a central unit of work that first fetches the waveform data via the seedlink protocol and event data via event bus or FDSN web service, then collects and cuts waveforms segments according to a custom configuration, and eventually triggers custom processing (ewricasiria and ewricagm in the docker, but any processing can be implemented) whenever configurable conditions are met. The final package, ewricawebapp is a web-based graphical user interface that can be opened in your local browser or deployed on your web server in order to visualize and check all output produced by the docker workflow in form of HTML pges, images and data in various formats (e.g., JSON, log text files). The EWRICA Docker package includes the following tools: ewricacore: Central unit for all Ewrica components and event/data listener ewricagm: Create ground motion maps via pre-trained Neural Network ewricasiria: Ewrica Source Inversion and Rapid Impact Assessment Python package ewricawebapp: Ewrica web portal and GUI demo grond: A probabilistic earthquake source inversion framework (Heimann et al., 2018) stationsxml-archive: Storage repository for synchronizing Station XMLs
    Description: Other
    Description: License: GNU General Public License, Version 3, 29 June 2007 Copyright (C) 2023 Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Potsdam, Germany (Riccardo Zaccarelli). ewricacore, ewricagm, ewricasiria and ewricawebapp is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see 〈https://www.gnu.org/licenses/〉.
    Keywords: Early-Warning and Rapid Impact Assessment with real-time GNSS in the Mediterranean ; EWRICA ; source inversion ; real time seismic data ; shakemaps ; GNSS ; Earth Remote Sensing Instruments 〉 Passive Remote Sensing 〉 Positioning/Navigation 〉 GNSS ; EARTH SCIENCE 〉 HUMAN DIMENSIONS 〉 NATURAL HAZARDS 〉 EARTHQUAKES ; EARTH SCIENCE 〉 HUMAN DIMENSIONS 〉 NATURAL HAZARDS 〉 TSUNAMIS ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEODETICS ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 EARTHQUAKES
    Type: Software , Software
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  • 6
    Publication Date: 2023-09-21
    Description: Abstract
    Description: The increasingly high number of big data applications in seismology has made quality control tools to filter, discard, or rank data of extreme importance. In this framework, machine learning algorithms, already established in several seismic applications, are good candidates to perform the task flexibility and efficiently. sdaas (seismic data/metadata amplitude anomaly score) is a Python library and command line tool for detecting a wide range of amplitude anomalies on any seismic waveform segment such as recording artifacts (e.g., anomalous noise, peaks, gaps, spikes), sensor problems (e.g., digitizer noise), metadata field errors (e.g., wrong stage gain in StationXML). The underlying machine learning model, based on the isolation forest algorithm, has been trained and tested on a broad variety of seismic waveforms of different length, from local to teleseismic earthquakes to noise recordings from both broadband and accelerometers. For this reason, the software assures a high degree of flexibility and ease of use: from any given input (waveform in miniSEED format and its metadata as StationXML, either given as file path or FDSN URLs), the computed anomaly score is a probability-like numeric value in [0, 1] indicating the degree of belief that the analyzed waveform represents an anomaly (or outlier), where scores ≤0.5 indicate no distinct anomaly. sdaas can be employed for filtering malformed data in a pre-process routine, assign robustness weights, or be used as metadata checker by computing randomly selected segments from a given station/channel: in this case, a persistent sequence of high scores clearly indicates problems in the metadata
    Keywords: Machine learning ; Isolation forest ; Sesimic data anomaly detection ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 EARTHQUAKES ; EARTH SCIENCE SERVICES 〉 DATA MANAGEMENT/DATA HANDLING ; In Situ Land-based Platforms 〉 GEOPHYSICAL STATIONS/NETWORKS ; In Situ/Laboratory Instruments 〉 Magnetic/Motion Sensors 〉 Seismometers 〉 SEISMOMETERS
    Type: Software , Software
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  • 7
    Publication Date: 2023-09-27
    Description: Abstract
    Description: Ground motion models (GMM) have been employed in several domains, from traditional seismic hazard and risk analysis to more recent shakemaps and rapid loss assessment. In this framework, eGSIM is a Python package and web application intended to help engineers and seismologist in understanding how different models compare for specific earthquake scenarios and how well they fit to observed ground motion data, producing results as visual plot or tabular data in standard, accessible and convenient formats (CSV, HDF, JSON and several image formats). Based on OpenQuake, a popular open-source Python library for seismic hazard and risk analysis, eGSIM incorporates and makes available in two user-friendly interfaces hundreds of published GMMs implemented and tested in OpenQuake: an online graphical user interface (GUI) accessible at https://egsim.gfz-potsdam.de, ideal for comparisons that can be visualized or downloaded as images, and a web application programming interface (web API), implemented along the lines of popular seismological web services (FDSN), more suited for comparisons that may be automatized in scheduled jobs, or need to be integrated into custom code and further processed in the user's own workflows. By incorporating databases in form of so-called flatfiles (ESM) and regionalizations derived from seismic hazard models (SHARE, ESHM20), eGSIM allows users to seamlessly select data for comparison and models for comparison based on regions of interest. It also features management scripts to smoothly incorporate new flatfiles or regionalizations from future research projects.Moreover, via the generation of flatfile templates based on a custom selection of GMMs, and the possibility to upload user-defined flatfiles, eGSIM facilitates the non-trivial task of compiling data for model comparison, and can be used to analyze ground motions from any data set recorded anywhere in the world, including rapid analysis of earthquake records following large events.
    Keywords: Ground motion model ; PSHA ; OpenQuake ; Strong motion database ; flatfile ; web API ; EARTH SCIENCE 〉 HUMAN DIMENSIONS 〉 NATURAL HAZARDS 〉 EARTHQUAKES ; EARTH SCIENCE SERVICES 〉 DATA ANALYSIS AND VISUALIZATION ; EARTH SCIENCE SERVICES 〉 WEB SERVICES ; EARTH SCIENCE SERVICES 〉 WEB SERVICES 〉 DATA PROCESSING SERVICES ; science 〉 materials science 〉 engineering 〉 seismic engineering
    Type: Software , Software
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  • 8
    Publication Date: 2023-11-23
    Description: Abstract
    Description: Preparation of technical reports can be unwieldy. However, a significant proportion of the document structure is often standardised. The GFZ Report Generator is a Python 2.7 application meant to ease this process by (i) automatically generating the standardised figures and tables, (ii) creating a report template pre-filled with this standard content, and which meets the GFZ style requirements, and (iii) providing a browser-based GUI with a text editor where users can add content to the report, generate and inspect the HTML and PDF versions on the fly as they are editing, track changes and revert to previous versions, and easily control the document structure and formatting from within the text by typing special characters in reStructuredText, an easy-to-read, what-you-see-is-what-you-get plaintext markup syntax. The GFZ Report Generator is quite flexible and by the use of tailor-made templates can be adapted easily to other use cases, where part of a document is based on standardised figures and section structure. For example, the software is deployed at GEOFON to generate both seismic network reports and annual reports. For the former, GEOFON also offers an online service (https://geofon.gfz-potsdam.de/waveform/reportgenerator/) where PIs and others can easily generate report templates pre-filled with network-specific content (e.g., probability density functions plots) and available online for editing. In this process, the deployed instance of the GFZ Report Generator proved to be useful for finding some classes of problems with the data and metadata stored at GEOFON.
    Keywords: seismic report generator ; restructured text ; online text editor ; EARTH SCIENCE SERVICES 〉 DATA ANALYSIS AND VISUALIZATION 〉 GEOGRAPHIC INFORMATION SYSTEMS 〉 WEB-BASED GEOGRAPHIC INFORMATION SYSTEMS ; EARTH SCIENCE SERVICES 〉 DATA MANAGEMENT/DATA HANDLING 〉 DATA DELIVERY ; EARTH SCIENCE SERVICES 〉 METADATA HANDLING 〉 METADATA TRANSFORMATION/CONVERSION ; EARTH SCIENCE SERVICES 〉 WEB SERVICES 〉 INFORMATION MANAGEMENT SERVICES 〉 GAZETTEER SERVICE
    Type: Software , Software
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  • 9
    Publication Date: 2024-03-28
    Description: Abstract
    Description: This archive disseminated through the GFZ-Data Service includes both results and information as-sociated to Bindi et al. (2023). In particular, the archive includes a seismic catalogue reporting ener-gy magnitude Me estimated form vertical P-waves recorded at teleseismic distances in the range 20°≤ D ≤ 98°, following Di Giacomo et al (2008, 2010). The catalogue is built considering 6349 earth-quakes included in the GEOFON (Quinteros et al, 2021) catalogue with moment magnitude Mw larger than 5 and occurring after 2011. Tools used to compute the energy magnitude are free available. In particular, we used stream2segment (Zaccarelli, 2018) to download data from IRIS (https://ds.iris.edu/ds) and EIDA (Strollo et al., 2021) repositories, and me-compute [Zaccarelli, 2023) to process waveforms and compute Me. The methodology applied to me-compute is also implemented as add-on for SeicomP (GFZ and Gempa, 2020) in order to allow the real time computation of Me (https://github.com/SeisComP/scmert).
    Description: Other
    Description: Version History: 19 February 2024: release of first version 28 March 2024: release of v.1.1 Addition of the complete list of references for the seismic networks analysed with me-compute as described in Bindi et al. (2024, ESSD). The list is provided as additional txt file in the data download section and all references were added to the XML metadata.
    Keywords: Energy magnitude ; seismic catalog ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 EARTHQUAKES ; geological process 〉 seismic activity 〉 earthquake
    Type: Dataset , Dataset
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