scholarly journals Seismic Monitoring and Data Processing at the Norwegian National Seismic Network

2018 ◽  
Vol 52 (I) ◽  
pp. 27-40 ◽  
Author(s):  
Lars Ottemöller ◽  
Marte Louise Strømme ◽  
Berit Marie Storheim

Lars Ottemöller, Marte Louise Strømme and Berit Marie Storheim report on Seismic Monitoring and Data Processing at the Norwegian National Seismic Network for the Summary of the Bulletin of the International Seismological Centre.

2019 ◽  
Vol 53 (II) ◽  
pp. 41-58
Author(s):  
Fatih Alver ◽  
Ömer Kılıçarslan ◽  
Kerem Kuterdem ◽  
Meltem Türkoğlu ◽  
M.Doruk Şentürk

Fatih Alver, Ömer Kılıçarslan, Kerem Kuterdem, Meltem Türkoğlu and M.Doruk Şentürk report on the Turkish National Seismic Network for the Summary of the Bulletin of the International Seismological Centre.  


2018 ◽  
Vol 52 (I) ◽  
pp. 41-52 ◽  
Author(s):  
Jari Kortström ◽  
Marja Uski ◽  
Kati Oinonen

Jari Kortström, Marja Uski and Kati Oinonen report on the Finnish National Seismic Network for the Summary of the Bulletin of the International Seismological Centre.


2014 ◽  
Vol 36 ◽  
pp. 61-67
Author(s):  
D. Pesaresi ◽  
M. Romanelli ◽  
C. Barnaba ◽  
P. L. Bragato ◽  
G. Durì

Abstract. The Centro di Ricerche Sismologiche (CRS, Seismological Research Centre) of the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS, Italian National Institute for Oceanography and Experimental Geophysics) in Udine (Italy) after the strong earthquake of magnitude M=6.4 occurred in 1976 in the Italian Friuli-Venezia Giulia region, started to operate the North-eastern Italy Seismic Network: it currently consists of 17 very sensitive broad band and 18 simpler short period seismic stations, all telemetered to and acquired in real time at the OGS-CRS data centre in Udine. Real time data exchange agreements in place with other Italian, Slovenian, Austrian and Swiss seismological institutes lead to a total number of about 100 seismic stations acquired in real time, which makes the OGS the reference institute for seismic monitoring of North-eastern Italy. The south-western edge of the OGS seismic network (Fig. 1) stands on the Po alluvial basin: earthquake localization and characterization in this area is affected by the presence of soft alluvial deposits. OGS ha already experience in running a local seismic network in high noise conditions making use of borehole installations in the case of the micro-seismicity monitoring of a local gas storage site for a private company. Following the ML = 5.9 earthquake that struck the Emilia region around Ferrara in Northern Italy on 20 May 2012 at 02:03:53 UTC, a cooperation of Istituto Nazionale di Geofisica e Vulcanologia, OGS, the Comune di Ferrara and the University of Ferrara lead to the reinstallation of a previously existing very broad band (VBB) borehole seismic station in Ferrara. The aim of the OGS intervention was on one hand to extend its real time seismic monitoring capabilities toward South-West, including Ferrara and its surroundings, and on the other hand to evaluate the seismic response at the site. We will describe improvements in running the North-eastern Italy Seismic Network, including details of the Ferrara VBB borehole station configuration and installation, with first results.


Author(s):  
Y. O. Gordienko ◽  
A. O. Lotoshko ◽  
O. O. Paplinskiy

The paper analyzes the methods of processing measurement data of the seismic observation method used in the International Seismic Monitoring System and the Main Center for Special Control of the State Space Agency of Ukraine to solve problems of monitoring nuclear tests at foreign test sites. The directions of improvement of known and development of new methods of processing of measuring data of seismic method of detection in the conditions of presence and absence of a priori information on the form of a seismic signal are defined. If the form of the expected seismic signal is known, then the monitoring of foreign test sites by the seismic grouping system can be realized by supplementing the method of controlled directional reception with a correlation scheme of measurement data processing. In the absence of information on the shape of the seismic signal, the monitoring of the test site is carried out by dividing the group into two subgroups, followed by the cross-correlation method between the original samples of each subgroup. For a network of three-component stations, if there is information about the shape of the expected seismic signal, the method of comparison with the reference signal is used. In the absence of reference signals, monitoring is implemented using system discriminant, which takes into account the kinetic and dynamic properties of the expected signal with a cell from a given area. Possibilities of application of seismic stations of the International system of seismic monitoring are analyzed, use of measuring data which for the decision of problems of monitoring of foreign landfills allows to reduce time of definition of parameters of a seismic event essentially. A feature of the signals registered by seismic stations of the International System is the presence of types of seismic waves characteristic of events with cells in the near zone. Implementation of monitoring of test sites is possible by taking into account the polarization and dynamic properties of seismic waves. The implementation of the proposed approaches will increase the efficiency of solving the problem of detecting nuclear explosions at foreign test sites.


2018 ◽  
Vol 89 (2A) ◽  
pp. 324-337 ◽  
Author(s):  
J. Antonio Vidal‐Villegas ◽  
Luis Munguía ◽  
J. Alejandro González‐Ortega ◽  
M. Alejandra Nuñez‐Leal ◽  
Erik Ramírez ◽  
...  

2021 ◽  
Author(s):  
Pauline Galea ◽  
Matthew Agius ◽  
George Bozionelos ◽  
Sebastiano D'Amico ◽  
Daniela Farrugia

<p>The Maltese islands are a small country 15 km wide by 30 km long located about 100 km south of Sicily, Italy. Since 2015 Malta has set up a national seismic network. The primary aim of this network is to monitor in real-time and to locate more accurately the seismicity close to the islands and the seismicity in the Sicily Channel, offshore between Sicily, Tunisia and Libya. This Channel presents a range of interesting and complex tectonic processes that have developed in response to various regional stress fields mainly as a result of the collision between the African plate with Europe. The Maltese islands are known to have been affected by a number of earthquakes originating in the Channel, with some of these events estimated to be very close to the islands.</p><p>The seismotectonic characteristics of the Sicily channel, particularly south of the Maltese islands, is not well understood. This situation is being partially addressed through an increase in the number of seismic stations on the Maltese archipelago. The Malta Seismic Network (FDSN code ML), managed by the Seismic Monitoring and Research Group, within the Department of Geosciences, University of Malta, currently comprises 8 broadband, 3-component stations over an area slightly exceeding 300 km<sup>2</sup>. We present a technical description of the MSN including quality control tests such as spectral analysis (Power Spectral Density and HVSR), station orientations and timings as well as examples of local and regional earthquakes recorded on the network. We describe the upgrades to real-time data transmission and archiving, and automated epicentre location for continuous seismic monitoring using the local network amalgamated with a virtual seismic network to monitor the seismicity in the extended Mediterranean region. Such a dense national network, besides improving epicentral location in the Sicily Channel, is providing valuable information on microearthquake activity known to occur in close proximity to the islands, which has been very difficult to study in the past. It also provides an important tool for analysing site response and site amplification related to underlying geology, which constitutes a major component of seismic hazard analysis on the islands. Furthermore, the increase in seismic stations to the seismic monitoring system provides more robust earthquake estimates for the tsunami monitoring/simulation system.</p><p>Funding for stations was provided by Interreg Italia-Malta projects (SIMIT and SIMIT-THARSY, Codes B1-2.19/11 and C1-3.2-57) and by Transport Malta.</p>


2012 ◽  
Vol 12 (11) ◽  
pp. 3545-3555 ◽  
Author(s):  
M. Walter ◽  
U. Schwaderer ◽  
M. Joswig

Abstract. In this study we describe the seismic analysis of precursory patterns of a rockfall in the "Rappenlochschlucht", a gorge located in the Vorarlberg Alps, Austria. The rockfall with an estimated volume of 15 000 m3 occurred on 10 May 2011 (10:48:43 UTC) and destroyed a massive bridge construction. Fortunately, the rockfall did not cause any casualties. A permanent seismic network consisting of three seismic small arrays was installed in July 2009 in 5 km distance to the gorge, at the Heumoes slope, in order to detect and locate slope-related fracture processes within a radius of a few hundred meters. By chance, the rockfall with an estimated equivalent local magnitude of ML,eq = 2.3 was recorded by the seismic network. We observed several smaller rockfall events up to three hours, and 12 fracture signals up to five hours prior to the rockfall. The smaller rockfalls and the fractures were both located in the vicinity of the source area where the main event emerged, applying absolute and relative localization methods. These specific types of fracture signals located near by the gorge "Rappenlochschlucht" have never been observed in almost two years of permanent seismic monitoring. We interpret these fractures with magnitudes between ML = 0.4 and −0.5 as precursory signals of the main rockfall event. The observed fractures and the weaker rockfalls are sequences of initial stress relief within the rock mass and mass transferring processes, respectively, finally causing the destructive main rockfall event. To investigate possible triggers of the destructive rockfall event, several meteorological and hydrological data as well as the local seismicity during that period of time were analyzed and discussed in detail in this study. Unfortunately, no triggering factor of the rockfall event was identified, and remains therefore unknown.


Sign in / Sign up

Export Citation Format

Share Document