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  • 1
    Publication Date: 2020-12-07
    Description: This report summarizes the seismicity in Switzerland and surrounding regions in the years 2015 and 2016. In 2015, the Swiss Seismological Service detected and located 735 earthquakes in the region under consideration. With a total of 20 earthquakes of magnitude ML C 2.5, the seismic activity of potentially felt events in 2015 was close to the average of 23 earthquakes over the previous 40 years. Seismic activity was above average in 2016 with 872 located earthquakes of which 31 events had ML C 2.5. The strongest event in the analyzed period was the ML 4.1 Salgesch earthquake, which occurred northeast of Sierre (VS) in October 2016. The event was felt in large parts of Switzerland and had a maximum intensity of V. Derived focal mechanisms and relative hypocenter relocations of aftershocks image a SSE dipping reverse fault, which likely also hosted an ML 3.9 earthquake in 2003. Another remarkable earthquake sequence in the Valais occurred close to Sion with four felt events (ML 2.7–3.2) in 2015/16. We associate this sequence with a system of WNW-ESE striking fault segments north of the Rhoˆne valley. Similarities with a sequence in 2011, which was located about 10 km to the NE, suggest the existence of an en-echelon system of basement faults accommodating dextral slip along the Rhoˆne-Simplon line in this area. Another exceptional earthquake sequence occurred close to Singen (Germany) in November 2016. Relocated hypocenters and focal mechanisms image a SW dipping transtensional fault segment, which is likely associated with a branch of the Hegau-Bodensee Graben. On the western boundary of this graben, micro-earthquakes close to Schlattingen (TG) in 2015/16 are possibly related to a NE dipping branch of the Neuhausen Fault. Other cases of earthquakes felt by the public during 2015/16 include earthquakes in the region of Biel, Vallorcine, Solothurn, and Savognin.
    Description: SwissEnergy (http:// www.energieschweiz.ch) and the Swiss Federal Office of Energy for the financial support of project GEOBEST-CH; Swiss Competence Center for Energy Research—Supply of Electricity (http://www.sccer-soe.ch); Swiss-AlpArray SINERGIA project CRSII2_154434/1 by the Swiss National Science Foundation (SNSF)
    Description: Published
    Description: 221–244
    Description: 2T. Sorgente Sismica
    Description: 1IT. Reti di monitoraggio
    Description: 5IT. Osservatori
    Description: JCR Journal
    Keywords: Seismicity ; Magnitude of completeness ; Focal mechanisms ; Seismotectonics ; Rhone-Simplon line ; Hegau-Bodensee graben ; Basel ; Aar massif ; 04. Solid Earth ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Limitation Availability
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  • 2
    Publication Date: 2021-02-12
    Description: This report summarizes the seismicity in Switzerland and surrounding regions in the years 2017 and 2018. In 2017 and 2018, the Swiss Seismological Service detected and located 1227 and 955 earthquakes in the region under considera- tion, respectively. The strongest event in the analysed period was the ML 4.6 Urnerboden earthquake, which occurred in the border region of cantons Uri, Glarus and Schwyz on March 6, 2017. The event was the strongest earthquake within Switzerland since the ML 5.0 Vaz earthquake of 1991. Associated ground motions indicating intensity IV were reported in a radius up to about 50 km and locally approached intensity VI in the region close to the epicentre. Derived focal mechanisms and relative hypocentre relocations of the immediate aftershocks image a NNW–SSE striking sinistral strike-slip fault. Together with other past events in this region, the Urnerboden earthquake suggests the existence of a system of sub-parallel strike-slip faults, likely within in the uppermost crystalline basement of the eastern Aar Massif. A vigorous earthquake sequence occurred close to Château-d’Oex in the Préalpes-Romandes region in western Switzer- land. With a magnitude of ML 4.3, the strongest earthquake of the sequence occurred on July 1, 2017. Focal mechanism and relative relocations of fore- and aftershocks image a NNE dipping normal fault in about 4 km depth. Two similarly oriented shallow normal-fault events occurred between subalpine Molasse and Préalpes units close to Châtel-St-Denis and St. Silvester in 2017/18. Together, these events indicate a domain of NE–SW oriented extensional to transtensional deformation along the Alpine Front between Lake Geneva in the west and the Fribourg Fault in the east. The structural complexity of the Fribourg Fault is revealed by an ML 2.9 earthquake near Tafers in 2018. The event images a NW–SE striking fault segment within the crystalline basement, which might be related to the Fribourg Fault Zone. Finally, the ML 2.8 Grenchen earthquake of 2017 provides a rare example of shallow thrust faulting along the Jura fold-and-thrust belt, indicating contraction in the northwestern Alpine foreland of Switzerland.
    Description: Published
    Description: id 4
    Description: 4T. Sismicità dell'Italia
    Description: JCR Journal
    Keywords: Seismicity ; Focal mechanisms ; Seismotectonics ; Urnerboden ; Aar Massif ; Château-d’oex ; Préalpes ; Fribourg ; Jura fold-and-thrust belt ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Limitation Availability
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  • 3
    Publication Date: 2022-02-11
    Description: Seismic event detection and phase picking are the base of many seismological workflows. In recent years, several publications demonstrated that deep learning approaches significantly outperform classical approaches, achieving human-like performance under certain circumstances. However, as studies differ in the datasets and evaluation tasks, it is unclear how the different approaches compare to each other. Furthermore, there are no systematic studies about model performance in cross-domain scenarios, that is, when applied to data with different characteristics. Here, we address these questions by conducting a large-scale benchmark. We compare six previously published deep learning models on eight data sets covering local to teleseismic distances and on three tasks: event detection, phase identification and onset time picking. Furthermore, we compare the results to a classical Baer-Kradolfer picker. Overall, we observe the best performance for EQTransformer, GPD and PhaseNet, with a small advantage for EQTransformer on teleseismic data. Furthermore, we conduct a cross-domain study, analyzing model performance on data sets they were not trained on. We show that trained models can be transferred between regions with only mild performance degradation, but models trained on regional data do not transfer well to teleseismic data. As deep learning for detection and picking is a rapidly evolving field, we ensured extensibility of our benchmark by building our code on standardized frameworks and making it openly accessible. This allows model developers to easily evaluate new models or performance on new data sets. Furthermore, we make all trained models available through the SeisBench framework, giving end-users an easy way to apply these models.
    Description: This work was supported by the Helmholtz Association Initiative and Networking Fund on the HAICORE@KIT partition. J. Münchmeyer acknowledges the support of the Helmholtz Einstein International Berlin Research School in Data Science (HEIBRiDS). The authors thank the Impuls-und Vernetzungsfonds of the HGF to support the REPORT-DL project under the grant agreement ZT-I-PF-5-53. This work was also partially supported by the project INGV Pianeta Dinamico 2021 Tema 8 SOME (CUP D53J1900017001) funded by Italian Ministry of University and Research “Fondo finalizzato al rilancio degli investimenti delle amministrazioni centrali dello Stato e allo sviluppo del Paese, legge 145/2018.” Open access funding enabled and organized by Projekt DEAL.
    Description: Published
    Description: e2021JB023499
    Description: 3T. Fisica dei terremoti e Sorgente Sismica
    Description: JCR Journal
    Keywords: seismic phase recognition ; deep learnig ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Limitation Availability
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  • 4
    Publication Date: 2023-02-21
    Description: We take advantage of the new large AlpArray Seismic Network (AASN) as part of the AlpArray research initiative (www.alparray.ethz.ch), to establish a consistent seismicity-catalogue for the greater Alpine region (GAR) for the time period 2016 January 1–2019 December 31. We use data from 1103 stations including the AASN backbone composed of 352 permanent and 276 (including 30 OBS) temporary broad-band stations (network code Z3). Although characterized by a moderate seismic hazard, the European Alps and surrounding regions have a higher seismic risk due to the higher concentration of values and people. For these reasons, the GAR seismicity is monitored and routinely reported in catalogues by a 11 national and 2 regional seismic observatories. The heterogeneity of these data set limits the possibility of extracting consistent information by simply merging to investigate the GAR's seismicity as a whole. The uniformly spaced and dense AASN provides, for the first time, a unique opportunity to calculate high-precision hypocentre locations and consistent magnitude estimation with uniformity and equal uncertainty across the GAR. We present a new, multistep, semi-automatic method to process ∼50 TB of seismic signals, combining three different software. We used the SeisComP3 for the initial earthquake detection, a newly developed Python library ADAPT for high-quality re-picking, and the well-established VELEST algorithm both for filtering and final location purposes. Moreover, we computed new local magnitudes based on the final high-precision hypocentre locations and re-evaluation of the amplitude observations. The final catalogue contains 3293 seismic events and is complete down to local magnitude 2.4 and regionally consistent with the magnitude 3+ of national catalogues for the same time period. Despite covering only 4 yr of seismicity, our catalogue evidences the main fault systems and orogens’ front in the region, that are documented as seismically active by the EPOS-EMSC manually revised regional bulletin for the same time period. Additionally, we jointly inverted for a new regional minimum 1-D P-wave velocity model for the GAR and station delays for both permanent station networks and temporary arrays. These results provide the base for a future re-evaluation of the past decades of seismicity, and for the future seismicity, eventually improving seismic-hazard studies in the region. Moreover, we provide a unique, consistent seismic data set fundamental to further investigate this complex and seismically active area. The catalogue, the minimum 1-D P-wave velocity model, and station delays associated are openly shared and distributed with a permanent DOI listed in the data availability section.
    Description: The AlpArray-Switzerland project is funded by the Swiss-AlpArray SINERGIA project CRSII2_154434/1 by Swiss National Science Foundation (SNSF).
    Description: Published
    Description: 921-943
    Description: 1T. Struttura della Terra
    Description: 4T. Sismicità dell'Italia
    Description: JCR Journal
    Keywords: Earthquake source observations ; Seismicity ; Tectonics ; Statistical seismology ; 04.06. Seismology ; 04.01. Earth Interior
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Limitation Availability
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  • 5
    Publication Date: 2023-02-21
    Description: Machine‐learning (ML) methods have seen widespread adoption in seismology in recent years. The ability of these techniques to efficiently infer the statistical properties of large datasets often provides significant improvements over traditional techniques when the number of data are large (millions of examples). With the entire spectrum of seismological tasks, for example, seismic picking and detection, magnitude and source property estimation, ground‐motion prediction, hypocenter determination, among others, now incorporating ML approaches, numerous models are emerging as these techniques are further adopted within seismology. To evaluate these algorithms, quality‐controlled benchmark datasets that contain representative class distributions are vital. In addition to this, models require implementation through a common framework to facilitate comparison. Accessing these various benchmark datasets for training and implementing the standardization of models is currently a time‐consuming process, hindering further advancement of ML techniques within seismology. These development bottlenecks also affect “practitioners” seeking to deploy the latest models on seismic data, without having to necessarily learn entirely new ML frameworks to perform this task. We present SeisBench as a software package to tackle these issues. SeisBench is an open‐source framework for deploying ML in seismology—available via GitHub. SeisBench standardizes access to both models and datasets, while also providing a range of common processing and data augmentation operations through the API. Through SeisBench, users can access several seismological ML models and benchmark datasets available in the literature via a single interface. SeisBench is built to be extensible, with community involvement encouraged to expand the package. Having such frameworks available for accessing leading ML models forms an essential tool for seismologists seeking to iterate and apply the next generation of ML techniques to seismic data.
    Description: Published
    Description: 1695–1709
    Description: 3T. Fisica dei terremoti e Sorgente Sismica
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 6
    Publication Date: 2021-02-08
    Description: We study the local seismicity in East Java around the Arjuno-Welirang volcanic complex that is connected via the Watukosek Fault System, to the spectacular Lusi eruption site. Lusi is a sediment-hosted hydrothermal system which has been erupting since 2006. It is fed by both mantellic and hydrothermal fluids, rising and mixing with the thermogenic gases and other fluids from shallower sedimentary formations. During a period of 24 months, we observe 156 micro-seismic earthquakes with local magnitudes ranging from ML0.5 to ML1.9, within our network. The events predominantly nucleate at depths of 8–13 km below the Arjuno-Welirang volcanic complex. Despite the geological evidence of active tectonic deformation and faulting observed at the surface, practically no seismicity is observed in the sedimentary basin hosting Lusi. Although we cannot entirely rule out artifacts due to an increased detection threshold in the sedimentary basin, the deficit in significant seismicity suggests aseismic deformation beneath Lusi due to the large amount of fluids that may lubricate the fault system. An analysis of focal mechanisms of nine selected events around the Arjuno-Welirang volcanic complex indicates predominantly strike-slip faulting activity in the region SW of Lusi. This type of activity is consistent with observable features such as fault escarpment, river deviation and railroad deformation; suggesting that the Watukosek fault system extends from the volcanic complex towards the NE of Java. Our results point out that the tectonic deformation of the region is characterized by a segmented fault system being part of a broader damage zone, rather than localized along a distinct fault plane.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
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  • 7
    Publication Date: 2014-12-16
    Description: On 27 February 2010 the Mw 8.8 Maule earthquake in Central Chile ruptured a well known seismic gap, which last broke in 1835. Shortly after the mainshock Chilean agencies (UC Santiago, UC Concepción) and the international seismological community (USA (IRIS), France (IPGP), UK (University of Liverpool), Germany (GFZ)) installed a total of 142 portable seismic landstations stations along the whole rupture zone in order to capture the aftershock activity. Additionally a network of 30 ocean bottom seismometers was deployed (IFM Geomar) in the northern portion of the rupture area for a three month period between 20 September 2010 and 25 December 2010. We present first results from local earthquake tomography based on arrival times from automatic detection algorithms and picking engines which are calibrated with manually picked events. The Vp and Vp/Vs velocity models will better illuminate the structure of the forearc including the downgoing slab, the sedimentary basins and the volcanic arc down to depths of 75 km. The 2D and 3D velocity models cover the northern part of the rupture Maule 2010 rupture zone between 33 ° and 36 °S. This region is characterized by pronounced crustal aftershock activity which started after a strong aftershock doublet (Mw=6.9) on 11 March 2010 near the city of Pichilemu (~34.5 °S) in the overriding plate. This pronounced cluster of crustal seismicity close to the city of Pichilemu will be the focus area with smaller node spacing of the velocity model.
    Type: Conference or Workshop Item , NonPeerReviewed
    Location Call Number Limitation Availability
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  • 8
    Publication Date: 2021-11-24
    Description: Seismic event detection and phase picking are the base of many seismological workflows. In recent years, several publications demonstrated that deep learning approaches significantly outperform classical approaches and even achieve human-like performance under certain circumstances. However, as most studies differ in the datasets and exact evaluation tasks studied, it is yet unclear how the different approaches compare to each other. Furthermore, there are no systematic studies how the models perform in a cross-domain scenario, i.e., when applied to data with different characteristics. Here, we address these questions by conducting a large-scale benchmark study. We compare six previously published deep learning models on eight datasets covering local to teleseismic distances and on three tasks: event detection, phase identification and onset time picking. Furthermore, we compare the results to a classical Baer-Kradolfer picker. Overall, we observe the best performance for EQTransformer, GPD and PhaseNet, with EQTransformer having a small advantage for teleseismic data. Furthermore, we conduct a cross-domain study, in which we analyze model performance on datasets they were not trained on. We show that trained models can be transferred between regions with only mild performance degradation, but not from regional to teleseismic data or vice versa. As deep learning for detection and picking is a rapidly evolving field, we ensured extensibility of our benchmark by building our code on standardized frameworks and making it openly accessible. This allows model developers to easily compare new models or evaluate performance on new datasets, beyond those presented here. Furthermore, we make all trained models available through the SeisBench framework, giving end-users an easy way to apply these models in seismological analysis.
    Type: Article , NonPeerReviewed
    Format: text
    Location Call Number Limitation Availability
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  • 9
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    In:  [Talk] In: EGU General Assembly 2017, 23.-28.04.2017, Vienna, Austria .
    Publication Date: 2018-05-28
    Type: Conference or Workshop Item , NonPeerReviewed
    Format: text
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  • 10
    Publication Date: 2021-11-23
    Description: Machine Learning (ML) methods have seen widespread adoption in seismology in recent years. The abilityof these techniques to efficiently infer the statistical properties of large datasets often provides significantimprovements over traditional techniques when the number of data are large(»millions of examples). Withthe entire spectrum of seismological tasks, e.g., seismic picking and detection, magnitude and source propertyestimation, ground motion prediction, hypocentre determination; among others, now incorporating ML ap-proaches, numerous models are emerging as these techniques are further adopted within seismology. To evaluatethese algorithms, quality controlled benchmark datasets that contain representative class distributions are vital.In addition to this, models require implementation through a common framework to facilitate comparison.Accessing these various benchmark datasets for training and implementing the standardization of models iscurrently a time-consuming process, hindering further advancement of ML techniques within seismology. Thesedevelopment bottlenecks also affect ’practitioners’ seeking to deploy the latest models on seismic data, withouthaving to necessarily learn entirely new ML frameworks to perform this task. We present SeisBench as a soft-ware package to tackle these issues. SeisBench is an open-source framework for deploying ML in seismology.SeisBench standardises access to both models and datasets, whilst also providing a range of common processingand data augmentation operations through the API. Through SeisBench, users can access several seismologicalML models and benchmark datasets available in the literature via a single interface. SeisBench is built to beextensible, with community involvement encouraged to expand the package. Having such frameworks availablefor accessing leading ML models forms an essential tool for seismologists seeking to iterate and apply the nextgeneration of ML techniques to seismic data.
    Type: Article , NonPeerReviewed
    Format: text
    Location Call Number Limitation Availability
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