scholarly journals Seismic Monitoring at the Turkish National Seismic Network (TNSN)

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. 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.


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.


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.


Author(s):  
Pauline Galea ◽  
Matthew R. Agius ◽  
George Bozionelos ◽  
Sebastiano D’Amico ◽  
Daniela Farrugia

Abstract The Sicily Channel, situated on the leading edge of the African plate as it collides with Europe, presents a range of interesting and complex tectonic processes that have developed in response to various regional stress fields. The characterization and interpretation of the seismic activity, however, still presents a challenge. The Maltese islands, lying approximately 100 km to the south of Sicily, are known to have been affected by a number of earthquakes in the Channel, with some of these events estimated to be very close to the islands. Yet, in the absence of nearby seismic instruments, an accurate evaluation and mapping of small magnitude seismicity, and, hence, the identification of unmapped active faults in the region, remains a challenge. This situation is being partially addressed through the deployment of more seismic stations on the Maltese archipelago. The Malta Seismic Network (MSN; International Federation of Digital Seismograph Networks code ML, see Data and Resources), managed by the Seismic Monitoring and Research Group, within the Department of Geosciences, University of Malta, currently comprises eight broadband, three-component stations covering an area of, approximately, 315  km2. Continuous seismic monitoring is possible following upgrades to real-time data transmission and automated epicenter location, coupled with a virtual seismic network established through SeisComP3, and focused mainly on the Mediterranean region. Such a dense national network, besides improving epicentral location in the Sicily Channel, will provide 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 will also provide opportunities to study shallow crustal structure, site response on different geological substrates, microseismic noise propagation, and effects of anthropogenic activities. Here, we give a technical description of the MSN and an appraisal of its potential.


2015 ◽  
Vol 63 (1) ◽  
pp. 17-44 ◽  
Author(s):  
Jacek Trojanowski ◽  
Beata Plesiewicz ◽  
Jan Wiszniowski

2013 ◽  
Vol 36 ◽  
pp. 11-16 ◽  
Author(s):  
A. D'Alessandro ◽  
A. Gervasi ◽  
I. Guerra

Abstract. The Calabrian Arc is an area of high seismic hazard, in the past often affected by destructive earthquakes. The seismicity of the Calabrian region is monitored by the Italian National Seismic Network integrated by the Calabrian Regional one and, in the last three years, by the Pollino temporary array. We have applied the Seismic Network Evaluation through Simulation to assess the individual contribution of each network in locating earthquakes with epicentres in the Calabrian region and surrounding. We shows that the Calabrian Regional Seismic Network greatly improves the quality of the coverage in almost the Calabria territory except in the Crotone Basin, in the Serre and in the offshore areas. We show that the contribution of the Pollino temporary array is instead restricted to a very small area centred on the Pollino Chain. Due to the presence in the Serre of important seismogenic volumes, which in the past have generated destructive earthquakes, it would be opportune to add at least several seismic stations in this area and surrounding to improve the seismic monitoring.


2016 ◽  
Vol 59 ◽  
Author(s):  
Milena Moretti ◽  
Silvia Pondrelli ◽  
Lucia Margheriti ◽  
Luigi Abruzzese ◽  
Mario Anselmi ◽  
...  

<p>At 01:36 UTC (03:36 local time) on August 24th 2016, an earthquake Mw 6.0 struck an extensive sector of the central Apennines (coordinates: latitude 42.70° N, longitude 13.23° E, 8.0 km depth). The earthquake caused about 300 casualties and severe damage to the historical buildings and economic activity in an area located near the borders of the Umbria, Lazio, Abruzzo and Marche regions. The Istituto Nazionale di Geofisica e Vulcanologia (INGV) located in few minutes the hypocenter near Accumoli, a small town in the province of Rieti. In the hours after the quake, dozens of events were recorded by the National Seismic Network (Rete Sismica Nazionale, RSN) of the INGV, many of which had a ML &gt; 3.0. The density and coverage of the RSN in the epicentral area meant the epicenter and magnitude of the main event and subsequent shocks that followed it in the early hours of the seismic sequence were well constrained. However, in order to better constrain the localizations of the aftershock hypocenters, especially the depths, a denser seismic monitoring network was needed. Just after the mainshock, SISMIKO, the coordinating body of the emergency seismic network at INGV, was activated in order to install a temporary seismic network integrated with the existing permanent network in the epicentral area. From August the 24th to the 30th, SISMIKO deployed eighteen seismic stations, generally six components (equipped with both velocimeter and accelerometer), with thirteen of the seismic station transmitting in real-time to the INGV seismic monitoring room in Rome. The design and geometry of the temporary network was decided in consolation with other groups who were deploying seismic stations in the region, namely EMERSITO (a group studying site-effects), and the emergency Italian strong motion network (RAN) managed by the National Civil Protection Department (DPC). Further 25 BB temporary seismic stations were deployed by colleagues of the British Geological Survey (BGS) and the School of Geosciences, University of Edinburgh in collaboration with INGV. All data acquired from SISMIKO stations, are quickly available at the European Integrated Data Archive (EIDA). The data acquired by the SISMIKO stations were included in the preliminary analysis that was performed by the Bollettino Sismico Italiano (BSI), the Centro Nazionale Terremoti (CNT) staff working in Ancona, and the INGV-MI, described below.</p>


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