BormannPeter, SaulJoachim, . (2008). The New IASPEI Standard Broadband Magnitude m B
. Seismological Research Letters, 79(5), 698–705.
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Bormann Peter, Saul Joachim, . (2009). A Fast, Non-saturating Magnitude Estimator for Great Earthquakes
. 0895-0695, 80(5), 808–816.
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McNamara D E, Hutt C R, Gee L S, Benz H M, Buland R P, . (2009). A Method to Establish Seismic Noise Baselines for Automated Station Assessment
. Seismological Research Letters, 80(4), 628–637.
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Ammon Charles J, Lay Thorne, Simpson David W, . (2010). Great Earthquakes and Global Seismic Networks
. Seismological Research Letters, 81(6), 965–971.
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Francisco Bravo, Pablo Koch, Sebastian Riquelme, Mauricio Fuentes, Jaime Campos. (2019). Slip Distribution of the 1985 Valparaíso Earthquake Constrained with Seismic and Deformation Data (Vol. 90).
Abstract: The 2017 Valparaíso seismic sequence calls attention to the potential seismic hazard for a megathrust earthquake in central Chile. Previous large historic earthquakes have been studied to improve our knowledge of the seismotectonic context in this region. In this work, we studied the slip distribution of the 3 March 1985 Mw 8.0 Valparaíso earthquake. To model this event, we use a finite‐fault model and a linear inversion scheme, incorporating data of near‐field displacement, surface waves, and P, SH, and PP waves. The results show that the rupture propagated 90 km southward and 80 km northward from the hypocenter, with a total duration of 65 s. The slip is concentrated mainly on two patches of the rupture between 20 and 40 km depth. The patch of maximum slip is near the nucleation zone. The obtained slip distribution is in agreement with the asperities model, which describes the seismicity of central Chile. We confirm that the source did not break the upper part of the subduction interface and that a large tsunamigenic potential is still present in this region. GeoRef Subject
Programme: 133
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Helle A. Pedersen, Nicolas Leroy, Dimitri Zigone, Martin Vallée, Adam T. Ringler, David C. Wilson. (2020). Using Component Ratios to Detect Metadata and Instrument Problems of Seismic Stations: Examples from 18 Yr of GEOSCOPE Data (Vol. 91).
Abstract: Replacement or deterioration of seismic instruments and the evolution of the installation conditions and sites can alter the seismic signal in very subtle ways; therefore, it is notoriously difficult to monitor the signal quality of permanent seismic stations. We present a simple way to characterize and monitor signal quality, using energy ratios between each pair of the three components, as a complement to existing methods. To calculate stable daily energy ratios over a large frequency range (0.01–5 Hz), we use the daily median energy ratio over all 5 min windows within the day. The method is applied to all GEOSCOPE stations, for continuous BH channel data collected since 2001. We show applications to identify past gain problems (stations ROCAM and CRZF), to provide feedback after field interventions at remote sites (Antarctic station DRV), and to shed light on complex instrument problems (stations ECH and KIP). Our results show that component energy ratios have excellent time resolution and that they are visually simple for identification of problems. They can be used both for ongoing continuous monitoring of the signal quality, or as a tool to identify past problems. The Python code to produce the results in this work and the Python code for daily monitoring used by GEOSCOPE are available (see Data and Resources).
Programme: 133
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Andrea Chiang, Gene A. Ichinose, Doug S. Dreger, Sean R. Ford, Eric M. Matzel, Steve C. Myers, W. R. Walter. (2018). Moment Tensor Source‐Type Analysis for the Democratic People’s Republic of Korea–Declared Nuclear Explosions (2006–2017) and 3 September 2017 Collapse Event (Vol. 89). Bachelor's thesis, , .
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Robert E. Anthony, Adam T. Ringler, Michael DuVernois, Kent R. Anderson, David C. Wilson. (2021). Six Decades of Seismology at South Pole, Antarctica: Current Limitations and Future Opportunities to Facilitate New Geophysical Observations (Vol. 92).
Abstract: Seismograms from the South Pole have been important for seismological observations for over six decades by providing (until 2007) the only continuous seismic records from the interior of the Antarctic continent. The South Pole, Antarctica station has undergone many updates over the years, including conversion to a digital recording station as part of the Global Seismographic Network (GSN) in 1991 and being relocated to multiple deep (>250 m) boreholes 8 km away from the station in 2003 (and renamed to Quiet South Pole, Antarctica [QSPA]). Notably, QSPA is the second most used GSN station by the National Earthquake Information Center to pick phases used to rapidly detect and locate earthquakes globally, and has been used for a variety of glaciological and oceanography studies. In addition, it is the only seismic station on the Earth where low‐frequency (<5 mHz), normal‐mode oscillations of the planet excited by large earthquakes can be recorded without influence from Earth’s rotation, and most of the direct effects of the solid Earth tide vanish. However, the current sensors are largely 1980s vintage, and, while able to make some lower‐frequency observations from earthquakes, the borehole sensors appear unable to resolve ambient ground motions at frequencies lower than 25 mHz due to instrument noise and contamination from magnetic field variations. Recently developed borehole sensors offer the potential to extend background noise observations to below 3 mHz, which would substantially improve the fidelity and scientific value of seismic observations at South Pole. Through collaboration with the IceCube Neutrino Observatory, the opportunity exists to emplace a modern very broadband seismometer near the base (>2 km depth) of the Antarctic ice cap, which could lead to unprecedented seismic observations at long periods and facilitate a broad spectrum of Earth science studies.
Programme: 133
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James K. Kleckner, Kyle B. Withers, Eric M. Thompson, John M. Rekoske, Emily Wolin, Morgan P. Moschetti. (2022). Automated Detection of Clipping in Broadband Earthquake Records (Vol. 93).
Abstract: Because the amount of available ground‐motion data has increased over the last decades, the need for automated processing algorithms has also increased. One difficulty with automated processing is to screen clipped records. Clipping occurs when the ground‐motion amplitude exceeds the dynamic range of the linear response of the instrument. Clipped records in which the amplitude exceeds the dynamic range are relatively easy to identify visually yet challenging for automated algorithms. In this article, we seek to identify a reliable and fully automated clipping detection algorithm tailored to near‐real‐time earthquake response needs. We consider multiple alternative algorithms, including (1) an algorithm based on the percentage difference in adjacent data points, (2) the standard deviation of the data within a moving window, (3) the shape of the histogram of the recorded amplitudes, (4) the second derivative of the data, and (5) the amplitude of the data. To quantitatively compare these algorithms, we construct development and holdout datasets from earthquakes across a range of geographic regions, tectonic environments, and instrument types. We manually classify each record for the presence of clipping and use the classified records. We then develop an artificial neural network model that combines all the individual algorithms. Testing on the holdout dataset, the standard deviation and histogram approaches are the most accurate individual algorithms, with an overall accuracy of about 93%. The combined artificial neural network method yields an overall accuracy of 95%, and the choice of classification threshold can balance precision and recall.
Programme: 133
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Carlo Cauzzi, Susana Custódio, Christos P. Evangelidis, Giovanni Lanzano, Lucia Luzi, Lars Ottemöller, Helle Pedersen, Reinoud Sleeman. (2021). Preface to the Focus Section on European Seismic Networks and Associated Services and Products (Vol. 92).
Abstract: Most of the articles of this focus section serve as good examples in the open science domain, in which data are expected to be “findable, accessible, interoperable, and reusable” (Wilkinson et al., 2016). In many contributions, emphasis is placed on quality: as automated access to seismological archives via standardized web services emerges as the preferred user strategy, ensuring the high quality of data and metadata becomes more and more important (e.g., Büyükakpınar et al., 2021; Cambaz et al., 2021; Carrilho et al., 2021; Evangelidis et al., 2021; Mader and Ritter, 2021; Ottemöller et al., 2021; Péquegnat et al., 2021; Stammler et al., 2021; Strollo et al., 2021). Quality is especially important at a time when very large datasets are increasingly being processed routinely and “blindly” in machine‐learning approaches. The vast majority of seismological data centers already manage multisensor archives (seismometers, accelerometers, infrasound, amphibian seismological instruments, high‐rate global navigation satellite systems, etc.), and the inclusion of new types of data (e.g., rotational sensors, low‐cost instrumentation, and synthetic waveforms) in seismological archives poses new challenges and prompts for new technical solutions and standards for data archiving, metadata preparation, quality checks, data dissemination, and processing. A particular challenge over the next few years (Quinteros, Carter, et al., 2021) is the upcoming massive growth of data volume, due in particular to new instruments (large‐N experiments and distributed acoustic sensing systems) but also to increased volumes of traditional seismic data. It is expected that multisensor experiments will progressively dominate the technical and scientific discussion in geosciences in the coming decade, spurred by the societal need to develop multidisciplinary, multihazard science and research products. Joining forces and competences is therefore key to addressing future challenges: the EarthScope Consortium was recently established in the United States, and the European Plate Observing System (EPOS) was created as the framework to integrate all geoscience services in the greater European region. ORFEUS and its seismic network community strongly support the development and consolidation of EPOS by participating in the activities of its thematic core service for seismology.
Programme: 133
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