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Igel, Heiner
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Igel, Heiner
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- PublicationOpen AccessVERCE delivers a productive e-Science environment for seismology research(2015-10-07)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ; ; ; ; ; ; ; ; ;; ;; ; ; ;The VERCE project has pioneered an e-Infrastructure to support researchers using established simulation codes on high-performance computers in conjunction with multiple sources of observational data. This is accessed and organised via the VERCE science gateway that makes it convenient for seismologists to use these resources from any location via the Internet. Their data handling is made flexible and scalable by two Python libraries, ObsPy and dispel4py and by data services delivered by ORFEUS and EUDAT. Provenance driven tools enable rapid exploration of results and of the relationships between data, which accelerates understanding and method improvement. These powerful facilities are integrated and draw on many other e-Infrastructures. This paper presents the motivation for building such systems, it reviews how solid-Earth scientists can make significant research progress using them and explains the architecture and mechanisms that make their construction and operation achievable. We conclude with a summary of the achievements to date and identify the crucial steps needed to extend the capabilities for seismologists, for solid-Earth scientists and for similar disciplines.100 98 - PublicationOpen Access6C Recordings at Active VolcanoesNear field recordings and thus finite source inversions of volcano-induced events often suffer from unaccounted effects of local tilt, saturation of classical instrumentation, unknown shallow velocity structure and doubtful orientation of the instruments. In addition, if the station number is limited the results of moment tensor inversions are very often not well constrained. Recent advances in hardware development made it possible to install several very broadband, high sensitive rotational motion sensor, based on fibre optical gyroscope technology, in very close distance of an activate volcano, i.e. on Stromboli volcano in 2016 and 2018, respectively. Using this new instrument together with classical instrumentation (i.e., translational seismometer, infra sound and tilt meter) we were able to record four weeks of permanent strombolian activity at Stromboli during these two experiments. The resulting six axis measurements reveal clear rotations around all three coordinate axis. We are furthermore able to demonstrate how this six axis measurements can help to improve the location procedure due to the property of a fiver optic gyro to act as a physical wave polariser. We also demonstrate the application of a single site shallow velocity estimation using volcanic background noise only, which will further improve the reliability of the source mechanism estimate. As a concluding step we will demonstrate how the use of sparse 6C measurement might be able to reduce the ambiguity of moment tensor inversions of volcano related signals.
65 9 - PublicationOpen AccessListening the Womb of the Earth: iXblue sonars, transponder and rotational seismometers for extreme environment imaging and monitoring(2020-05-04)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ;iXblue company develops technologies to listen and image the Earth dynamics. Among them, Echoes high-resolution sub-bottom profilers, Seapix 3D multibeam echosounder, Canopus transponder and blueSeis rotational seismometers are particularly useful for imaging and monitoring marine and continental volcanic activities. Here, we present recent implementations and acquisitions of those systems, demonstrate the great potential of these technologies to record present and past volcanic dynamics in Hawaii, Stromboli, Sicilia and Eifel region, and emphasize their benefits to better anticipate volcanic hazard. The Hawaii island experienced a dramatic volcanic crisis during the summer of 2018. To demonstrate the potential of observing the complete ground motion in the nearfield of seismic sources, Geophysical Observatory (LMU, Munich, Germany), in cooperation with USGS Hawaiian Volcano Observatory (USA), installed a high sensitive rotational motion sensor (blueSeis-3A) near the erupting crater returning spectacular data for almost daily M5 seismic events due to the collapse of the caldera. BlueSeis-3A, based on fiber optical gyroscope technology, at very close distance from the Stromboli volcano in 2016 and 2018, was installed together with classical instrumentation (i.e., translational seismometer, infra sound and tilt meter) and recorded four weeks of permanent strombolian activity at Stromboli during these two experiments. The resulting six axis measurements reveal clear rotations around all three-coordinate axis. We are furthermore able to demonstrate how these six component measurements can helpto improve solving the inversion problem on large and complex system like volcanoes. Eight Canopus transponders are involved in an ERC project in underwater geodesy, the FOCUS project headed by IUEM laboratory (Brest, France). Together with a 6 km-longoptical fiber deployed across the trench at the base of the Etna volcano, two groups of four Canopus will be installed on tripods each side of the trench at 1500-2000 m of water depth. This will help quantify the speed of the southeastern flank collapsing of Etna volcano into the Ionian Sea.In collaboration with French, Belgian and German geoscience laboratories, Echoes 10 000 (10 kHz) sub-bottom profiler and Seapix 3D multibeam echosounder, both installed on the kiXkat cataraft and remotely controlled, were mobilized to produce images of the water column and sediments of a lake formed in a volcanic crater in Germany (Laacher See). By using Seapix to obtain backscatter profiles of elements in the water column, it was possible to clearly distinguish fish and gas bubbles, which demonstrates a potential for the development of an automatic gas detection module using the Seapix software. Meanwhile, the Echoes 10 000 provided high-resolution images of the architecture of the lake deposits and visualized in real time using Delph Software. More than 30 m of penetration with a theoretical 8 cm-resolution highlight paleoenvironmental and paleoclimatic reconstruction perspectives and 3D modeling of remobilized materials and tephra deposits from volcanic activity.33 9 - PublicationOpen AccessThe use of 6DOF measurement in volcano seismology – A first application to Stromboli volcanoVolcano seismology, while its value for surveillance of an active volcano is undebatable, is a very demanding field when it comes to station deployment, maintenance, and finally interpreting the measurements. Most valuable in the past was the deployment of arrays of sensors to evaluate the properties of the entire wavefield in order to classify, locate, and estimate the dominant mechanism of the corresponding sources. While very beneficial, an array of seismographs is very hard to maintain in a permanent installation at an active volcano. With the advent of new instrumentation based on fiber optic technology such as Distributed Acoustic Sensing (DAS) with fiber optic cables as well as Fiber-Optic Gyroscopes (FOG) the measurement of deformation and rotation, i.e., the gradient of the wavefield is feasible. The advantage of the FOG instrumentation with respect to DAS lies in the portability and ease of deployment, which is very similar to standard deployments of traditional seismometers. During a field campaign in summer 2018 we were able to install three FOGs together with classical broadband seismometers in close proximity to the active vents of Stromboli volcano (Italy). We show that with this new six-degrees-of-freedom (6DOF) measurement we are able to analyze the wavefield composition, a property normally reserved for array(s) of seismic sensors. As a first result, we can support earlier array-derived findings that a large portion of the wavefield at Stromboli volcano is formed by SV- and SH- type waves. We also present first locations of these signals facilitating the polarization properties of the combined measurement of gyroscopes and seismometers. They emphasize the benefit of recording wavefield gradients. In addition to these array-like results, the 6DOF recordings show a clear separation of at least three distinct groups of volcanic events of which two are already known and one represents a jetting event that appears nearly invisible for classical seismometers. However, rotational motions - or more general - gradients of the wavefield experience severe distortions by local velocity fluctuations and topography significantly complicating the application of 6DOF techniques at activate volcanoes.
107 7 - PublicationRestrictedSix Degree-of-Freedom Broadband Ground-Motion Observations with Portable Sensors: Validation, Local Earthquakes, and Signal Processing(2020-06-01)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; The additional observation of three components of rotational ground motions has benefitsfor tilt-seismometer coupling (e.g., ocean-bottom seismometry and volcano seismology),local site characterization, wavefield separation, source inversion, glacial and planetaryseismology, as well as the monitoring of structural health. Field applications have beenmostly hampered by the lack of portable sensors with appropriate broadband operationrange and weak-motion sensitivity. Here, we present field observations of the firstcommercial portable broadband rotation sensor specifically designed for seismology.The sensor is a three-component fiber-optic gyro strictly sensitive to ground rotation only.The sensor field performance and records are validated by comparing it with both arrayderivedrotation measurements and a navigation-type gyro. We present observations ofthe 2018 Mw 5.4 Hualien earthquake and the 2016 central Italy earthquake sequence.Processing collocated rotation and classical translation records shows the potential inretrieving wave propagation direction and local structural velocity from point measurementscomparable to small-scale arrays of seismic stations. We consider the availabilityof a portable, broadband, high sensitivity, and low self-noise rotation sensor to be a milestonein seismic instrumentation. Complete and accurate ground-motion observations(assuming a rigid base plate) are possible in the near, local, or regional field, openingup a wide range of seismological applications.177 13 - PublicationRestrictedTowards Addressing CPU-Intensive Seismological Applications in Europe(Springer Berlin Heidelberg, 2013)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Carpené, M.; CINECA, Bologna, Italy ;Klampanos, I. A.; University of Edinburgh, School of Informatics, UK ;Leong, S. H.; Leibniz Supercomputing Centre (LRZ), Garching, Germany ;Casarotti, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Danecek, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Ferini, G.; CINECA, Bologna, Italy ;Gemünd, A.; Fraunhofer Institute for Algorithms and Scientific Computing SCAI, Germany ;Krause, A.; University of Edinburgh, Edinburgh Parallel Computing Centre (EPCC), UK ;Krischer, L.; Ludwig-Maximilianis-University, Department of Earth and Environmental Sciences, Germany ;Magnoni, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Simon, M.; Ludwig-Maximilianis-University, Department of Earth and Environmental Sciences, Germany ;Spinuso, A.; The Royal Netherlands Meteorological Institute (KNMI), Netherlands ;Trani, L.; The Royal Netherlands Meteorological Institute (KNMI), Netherlands ;Atkinson, M.; University of Edinburgh, School of Informatics, UK ;Erbacci, G.; CINECA, Bologna, Italy ;Frank, A.; Leibniz Supercomputing Centre (LRZ), Garching, Germany ;Igel, H.; Ludwig-Maximilianis-University, Department of Earth and Environmental Sciences, Germany ;Rietbrock, H.; University of Liverpool, Department of Earth, Ocean and Ecological Sciences, UK ;Schwichtenberg, H.; Fraunhofer Institute for Algorithms and Scientific Computing SCAI, Germany ;Vilotte, J.; Institut de Physique du Globe de Paris (IPGP), France; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Advanced application environments for seismic analysis help geosci- entists to execute complex simulations to predict the behaviour of a geophysical system and potential surface observations. At the same time data collected from seismic stations must be processed comparing recorded signals with predictions. The EU-funded project VERCE (http://verce.eu/) aims to enable specific seismological use-cases and, on the basis of requirements elicited from the seis- mology community, provide a service-oriented infrastructure to deal with such challenges. In this paper we present VERCE’s architecture, in particular relating to forward and inverse modelling of Earth models and how the, largely file-based, HPC model can be combined with data streaming operations to enhance the scala- bility of experiments. We posit that the integration of services and HPC resources in an open, collaborative environment is an essential medium for the advancement of sciences of critical importance, such as seismology.190 24 - PublicationOpen AccessRotational motions from the 2016, Central Italy seismic sequence, as observed by an underground ring laser gyroscope(2018)
; ; ; ; ; ; ; ; ; ; ; ; ; ;; We present the analysis of rotational and translational ground motions from earthquakes recorded during October–November 2016, in association with the Central Italy seismic sequence. We use co-located measurements of the vertical ground rotation rate from a large ring laser gyroscope and the three components of ground velocity from a broad-band seismometer. Both instruments are positioned in a deep underground environment, within the Gran Sasso National Laboratories of the Istituto Nazionale di Fisica Nucleare. We collected dozens of events spanning the 3.5–5.9 magnitude range and epicentral distances between 30 and 70 km. This data set constitutes an unprecedented observation of the vertical rotational motions associated with an intense seismic sequence at local distance. Under the plane-wave approximation we process the data set in order to get an experimental estimation of the events backazimuth. Peak values of rotation rate (PRR) and horizontal acceleration (PGA) are markedly correlated, according to a scaling constant which is consistent with previous measurements from different earthquake sequences. We used a prediction model in use for Italy to calculate the expected PGA at the recording site, obtaining consequently predictions for PRR. Within the modelling uncertainties, predicted rotations are consistent with the observed ones, suggesting the possibility of establishing specific attenuation models for ground rotations, like the scaling of peak velocity and peak acceleration in empirical ground-motion prediction relationships. In a second step, after identifying the direction of the incoming wavefield, we extract phase-velocity data using the spectral ratio of the translational and rotational components. This analysis is performed over time windows associated with the P-coda, S-coda and Lg phase. Results are consistent with independent estimates of shear wave velocities in the shallow crust of the Central Apennines295 123 - PublicationOpen AccessEstimating shallow Vs-profiles using 6C recordings of ground motionsThe combination of rotational and traditional translational motion sensors already proofed to form a new technique in measuring seismic wave field properties. While the estimation of phase velocities of surface waves from regional to teleseismic earthquakes was done both using Love waves and also Rayleigh waves, it was shown just recently that using ambient noise will facilitate the estimation of phase velocity of Love waves by directly relating vertical translational motions to transverse acceleration using a simple plane wave assumption. Up to now, however, in the advent of sensitive, broad band rotational motion sensor these ambient noise based estimates were made only using arrays of traditional seismometer. These array derived rotation estimates on the other hand inherently show sever restrictions especially if the incoming wave field is not strictly planar. Having access to the first highly sensitive and broadband fibre optic gyro based rotational sensor, we performed several experiments at an active volcano as well as in an urban environment. We here present the result of a joint analysis of phase velocities of Love and Rayleigh waves which than are further combined with a classical H/V estimate in a velocity model for P- and S Waves. The application of this technique using data from a network of 6C sensor will help to increase the reliability of moment tensor inversions at active volcanoes as well as forming an easier to use extension of microzonation in densely populated areas.
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