scholarly journals Organization of the stationary seismological observations point

2021 ◽  
Vol 43 (5) ◽  
pp. 232-240
Author(s):  
O. Z. Ganiev ◽  
T. A. Amashukeli ◽  
L. V. Farfuliak ◽  
K. V. Petrenko
Keyword(s):  
Seismic Waves ◽  
Observation Point ◽  
Observation Data ◽  
National Academy Of Sciences ◽  
Tectonic Structures ◽  
Seismic Observation ◽  
Data Registration ◽  
Seismological Data ◽  
Monitoring Process ◽  
Seismological Network

The Institute of Geophysics of the NASU organizes and carries out continuous regional and local seismic observations on the territory of Ukraine. The article presents a universal modern model of seismic activity monitoring process, which is used in most international seismological agencies (USGS, EMSC, NEIC) and describes a typical stationary point of seismological observations of the National Seismological Network of the Institute of Geophysics of NAS of Ukraine. Seismological network of observations is a complex of systems consisting of stationary seismological points of registration of seismic waves, the distributed system of transfer and collecting of the seismological information, and also the center of operative processing of the data arriving from data registration points. The process of conducting regime seismological observations of local and remote seismic events on the territory of Ukraine and adjacent regions is described. Some important aspects of the need for comprehensive processing of registered events to identify local earthquakes and assess the current activity of tectonic structures in Ukraine are presented. The seismological network of the National Seismological Center of the Institute of Geophysics of the National Academy of Sciences of Ukraine is represented by a small number of stationary observation points: «Kiev-IRIS», «MI02-Poltava», «MI03-Skvyra», «MI04-Dnipro», «MI05-Stepanivka», «MI07-Mykolaiv», «ODS-Odesa», «MIU-Kryvyi Rih», and «MI06-Kremenchug». This number of seismological observation points does not actually provide seismic observation data to the central, eastern and southern parts of the territory of Ukraine and does not allow to reliably determine the level and quantitative characteristics of its seismic hazard. The seismic recorder Guralp CMG-40T manufactured by the British company GURALP SYSTEMS LIMITED is offered as optimal for the conditions and financial realities of Ukraine when organizing a stationary seismic observation point. It is proposed to use the seismological processing package SeisComP, which works on the SeedLink protocol, which is the basis of the data collection system by the Internet. This software product is the de facto world standard in the field of seismological data processing.

An Optimum 2D Seismic-Wavefield Reconstruction in Densely and Nonuniformly Distributed Stations: The Metropolitan Seismic Observation Network in Japan

2021 ◽  
Author(s):  
Takahiro Shiina ◽  
Takuto Maeda ◽  
Masayuki Kano ◽  
Aitaro Kato ◽  
Naoshi Hirata
Keyword(s):  
Metropolitan Area ◽  
Seismic Waves ◽  
Seismic Station ◽  
Weighting Functions ◽  
Seismic Observation ◽  
Tokyo Metropolitan ◽  
Tokyo Metropolitan Area ◽  
Spatial Weights ◽  
Observation Network ◽  
Seismic Wavefield

Abstract We propose an optimization method for applying the seismic-wave gradiometry (SWG) method to a dense seismic station network consisting of nonuniformly distributed seismographs. As a nonuniformly distributed station array, we consider the station layout of the Metropolitan Seismic Observation Network (MeSO-net) operated in and around the Tokyo metropolitan area, Japan. In this study, thereby, we numerically investigate optimum shapes of weighting functions, which control the spatial weights of individual stations when estimating waveforms at any grid points in the SWG method, to reconstruct seismic wavefields propagating in the MeSO-net. The functions with isotropic spatial weights are found to be appropriate for wavefield reconstructions with seismic waves incoming from practically all directions, even for nonuniformly distributed stations. The reproducibility of the wavefields is greatly improved by changing the shapes of the spatial weights reflecting density of the stations. Further plausible wavefield reconstructions are made by considering the propagation directions of the seismic waves. In these cases, if the weight of a contribution for a wavefield reconstruction is larger at far stations with a direction perpendicular to the wave propagation direction, then the reproducibility of the waveforms is significantly increased. In addition, the spatial gradients of the amplitudes are well reproduced by the optimized SWG method even though the optimization only focused on the amplitudes. Therefore, our proposed optimization scheme can be used to accurately estimate seismic wavefields in a nonuniformly distributed station array. Actually, the weighting functions optimized in this study succeeded to reconstruct the seismic wavefield of a shallow crustal earthquake that occurred around the Tokyo metropolitan area, based on the observed seismograms obtained by the MeSO-net.

scholarly journals An Observational Process Ontology-Based Modeling Approach for Water Quality Monitoring

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 715
Author(s):  
Xiaolei Wang ◽  
Haitao Wei ◽  
Nengcheng Chen ◽  
Xiaohui He ◽  
Zhihui Tian
Keyword(s):  
Water Quality ◽  
Water Quality Monitoring ◽  
Process Models ◽  
Quality Monitoring ◽  
Quality Data ◽  
Observation Data ◽  
Process Ontology ◽  
Water Quality Data ◽  
Data Process ◽  
Monitoring Process

The increasing deterioration of aquatic environments has attracted more attention to water quality monitoring techniques, with most researchers focusing on the acquisition and assessment of water quality data, but seldom on the discovery and tracing of pollution sources. In this study, a semantic-enhanced modeling method for ontology modeling and rules building is proposed, which can be used for river water quality monitoring and relevant data observation processing. The observational process ontology (OPO) method can describe the semantic properties of water resources and observation data. In addition, it can provide the semantic relevance among the different concepts involved in the observational process of water quality monitoring. A pollution alert can be achieved using the reasoning rules for the water quality monitoring stations. In this study, a case is made for the usability testing of the OPO models and reasoning rules by utilizing a water quality monitoring system. The system contributes to the water quality observational monitoring process and traces the source of pollutants using sensors, observation data, process models, and observation products that users can access in a timely manner.

NIED’s V-net, the Fundamental Volcano Observation Network in Japan

2017 ◽  
Vol 12 (5) ◽  
pp. 926-931 ◽  
Author(s):  
Toshikazu Tanada ◽  
Hideki Ueda ◽  
Masashi Nagai ◽  
Motoo Ukawa ◽  
◽  
...  
Keyword(s):  
Distribution System ◽  
Seismic Waves ◽  
Earth Science ◽  
Pressure Vessels ◽  
Japan Meteorological Agency ◽  
Observation Data ◽  
File Transfer ◽  
Geospatial Information ◽  
Open Policy ◽  
Observation Network

In response to the recommendation of the Council for Science and Technology (Subdivision on Geodesy and Geophysics), the National Research Institute for Earth Science and Disaster Resilience (NIED) constructed a network of stations to observe 11 volcanoes: Tokachidake, Usuzan, Tarumaesan, Hokkaido-Komagatake, Iwatesan, Kusatsu-Shiranesan, Asamayama, Asosan, Kirishimayama, Unzendake, and Kuchinoerabujima. At each new station, a borehole seismograph and tiltmeter, a broadband seismograph, and a GNSS (GPS) were installed. Now, NIED has established 55 stations at 16 volcanoes, adding five volcanoes, namely, Izu- Oshima, Miyakejima, Ogasawara Iwoto, Mt. Fuji and Nasu-dake, and has constructed a new volcano observation network linking the 11 original volcanoes. NIED calls the combination of the new and earlier network the fundamental volcano observation network (V-net).Under a fully open policy, data from the borehole seismographs and tiltmeters, broadband seismographs, rain gauges, barometers,and quartz thermometers in the pressure vessels of the borehole seismographs and tiltmeters are distributed to institutes such as the Japan Meteorological Agency and universities in real time over NIED’s conventional seismic observation data distribution system. GNSS (GPS) data are regularly distributed to relevant research institutes, such as the Geospatial Information Authority of Japan, using file transfer protocol (FTP). In addition, since everyone can use these data for the promotion of volcano research and volcanic disaster prevention, it is now possible to view seismic waves and download data from NIED’s website.

Study on the Structural Characteristics of Martian Regolith by Ambient Noise Data from SEIS Observation

2020 ◽  
Author(s):  
Wanbo Xiao ◽  
Yanbin Wang
Keyword(s):  
Internal Structure ◽  
Ambient Noise ◽  
Landing Site ◽  
Observation Data ◽  
Polarization Analysis ◽  
S Wave ◽  
Long Distance ◽  
Seismic Observation ◽  
Noise Data ◽  
Martian Regolith

<p>For Earth and Moon, the seismic observation data is the most direct and effective means to detect their internal structure. However, due to the long distance between Mars and Earth and the harsh observation conditions on Mars, the exploration of Martian velocity structure model is a very challenging task. The InSight lander deployed the first seismic observation instrument SEIS (Seismic Experiment for Internal Structure) on the Mars’ surface after its successful landing on Mars on November 26, 2018. In this study, we performed horizontal-to-vertical spectral ratio (HVSR) and polarization analysis of three component VBB seismic waveforms recorded by the SEIS station released on the IRIS website. We are trying to constrain the thickness of the Martian regolith at the landing site of InSight from the SEIS data. The VBB ambient noise data we used are in HHV/HHU/HHW channels of ELYSE station in 30 Martian days. These data are predominantly ambient noise data caused by wind effects and do not contain any known marsquake data. We found that the HVSR curves from nearly all released data show two distinct peaks at 11.9 Hz and 24.5 Hz, respectively. Furthermore, we conducted particle motion and polarization analysis on these data in various frequency bands, which indicate that the ground motion at the highest peak show linearly polarized and vertically incident motion with a fixed azimuth. This could be explained by the S-wave resonance of the Martian regolith at the InSight landing site caused by the wave motion source from the wind induced motion of the lander. Using the possible S-wave velocity of the Martian regolith proposed by previous studies and the peak frequencies of the HVSR results in this study, thickness of the Martian regolith at the InSight landing site was obtained that is smaller than the pre-evaluated thickness (3~5 m) for the InSight mission.</p>

Combination of Earth Observation and Seismic Reflection Data Analysis for The Definition of Strike Slip Fault Zones in Central Crete

2020 ◽  
Author(s):  
Emmanuel Vassilakis ◽  
John Alexopoulos ◽  
Georgios-Pavlos Farangitakis
Keyword(s):  
Spatial Resolution ◽  
Seismic Reflection ◽  
Fault Zones ◽  
Strike Slip ◽  
Earth Observation ◽  
Strike Slip Fault ◽  
Aerial Photographs ◽  
Observation Data ◽  
Tectonic Structures ◽  
Earth Observation Data

<p>The general understanding of the major tectonic structures that are traced on Crete Island is of great importance to decipher the geodynamic regime of the leading edge of the overriding Aegean microplate and consequently Eurasia’s southernmost active margin. The aim of this multi-disciplinary methodology is to provide useful information for more reliable mapping of buried structures, which in turn supplement the dynamic and kinematic model of this key area of high interest.</p><p>Several indicators for the existence of oblique fault block displacement were identified with the use of earth observation data, as strike slip faulting expressions on the surface are more efficiently identified by vertical observations. Tectonic structures which are usually created along lateral displacements require different working scales. Hence, earth observation data (satellite images, aerial photographs) with various spatial characteristics need to be included.</p><p>Therefore, the methodology presented in this paper involves high spatial resolution digital elevation models and several remote sensing multispectral datasets, in many cases merged with higher spatial resolution panchromatic aerial photographs. The co-registration and ortho-rectification of all datasets proved to be a very significant part of this work in order to produce high resolution coloured 3D scenes at selected sites in central Crete, where the observed N-S trending strike slip fault zones crosscut arc parallel low angle normal faults and higher angle fault scarps.</p><p>Additionally, deep seismic reflection datasets along the major geomorphic structure of Messara basin were combined and highlighted the strike slip mechanism, since the continuation of the sub-vertical structures in depth has become clearer after the exact positioning of the sections and further interpretation.</p>

scholarly journals 2.5 dimensional model of mantle heterogeneities under the Ukrainian shield according to the gradients of the velocities of seismic waves

2020 ◽  
Vol 29 (2) ◽  
pp. 431-441
Author(s):  
Liudmyla O. Shumlianska ◽  
Yurii I. Dubovenko ◽  
Petro H. Pigulevskyy
Keyword(s):  
Velocity Gradient ◽  
Upper Mantle ◽  
Seismic Waves ◽  
Deep Structure ◽  
Ukrainian Shield ◽  
Depth Range ◽  
Tectonic Structures ◽  
P Waves ◽  
Useful Signal ◽  
Background Density

We analyze the basic techniques for the investigation of the deep structure of the mantle and the shortcomings of the models of mantle structures derived from them. Thus, we reveal that there is no analysis of the velocity field by means of analytical transformants. Therefore, we developed and tested a new approach to define the mantle boundaries based on the calculations of the sequence of P-waves velocity derivatives. As a result, we obtain some new set of velocity gradient distributions for the principal tectonic structures of the Ukrainian Shield along the composite profile. The boundaries of the mantle discontinuities according to the velocity gradient we define in a special manner to eliminate the false anomalies and the fluctuations of the velocity curves that occur due to the conversion of the hodograph into the mean velocities. The smoothing of the velocity curve we perform with a previously defined wavelength step being equal to 50 km. We treat the calculated velocity gradient anomalies as the useful signal response above the appropriate sections, which have different velocity accelerations levels inside the upper mantle. We assume that the mantle anomalies have the same physical background (density/viscosity distributions, temperature gradients etc.) within each range with the equal acceleration value. However, the singular points determined by the inflections of the gradient curve could be the possible boundaries of additional inhomogeneities within the mantle. We calculate both the 1st and the 2nd derivatives for the velocity curves obtained. The excesses 2.5-D model of the 1-th and 2-th gradient curves (the acceleration of the gradvp itself) determine the position of the max / min anomalies of gradvp at the consolidated seismic profile within the Ukrainian Shield. Finally, we analyze in detail the distribution of velocity gradients of P-waves within the upper mantle in the depth range of 50–750 km. It results in the identification of a series of additional gradient velocity boundaries within three principal structural horizons of the upper mantle (under ~ 200–300 km, ~ 410–500 km, and ~ 600–650 km respectively).

scholarly journals SPECTRAL ANALYSIS OF THE SEISMIC IMPACT IN NEAR ZONE OF STRONG EARTHQUAKE AND EFFECT DETAILS

2016 ◽  
Author(s):  
Э.Г. Геодакян ◽  
Дж.К. Карапетян ◽  
В.Б. Заалишвили ◽  
С.М. Оганесян ◽  
С.Н. Саргсян
Keyword(s):  
Spectral Analysis ◽  
Strong Earthquake ◽  
Seismic Waves ◽  
Geological Structure ◽  
Observation Point ◽  
Geological Environment ◽  
Seismic Effects ◽  
Near Zone ◽  
Seismic Impact ◽  
Instrumental Records

На основе цифровых инструментальных записей исследованы влияние геологической среды распространения сейсмических волн и геологического строения «инженерного» слоя под пунктом наблюдения на амплитудный уровень и частотный состав сейсмических воздействий The influence of the geological environment of seismic waves and the geological structure of the «engineering» layer under observation point on the level of amplitude and frequency composition of seismic effects are investigated on the basis of digital instrumental records

Sign in / Sign up

Export Citation Format

Share Document