Observatories and Research Facilities for EUropean Seismology
Volume 4, no 1 May 2002 Orfeus Newsletter


The seismic network of the Geophysical Survey of the Russian Academy of Sciences

O. Starovoit and V. Mishatkin

Geophysical Survey of Russian Academy of Science, 249020, Kaluga region, Obninsk, Lenin str. 189

Introduction - Teleseismic network - Regional networks

Introduction

The seismic network of Russia, responsible for seismic monitoring of the whole country, has a hierarchical three-level structure. It includes 1 teleseismic network and 9 regional seismic networks which in its turn consist of local networks. The Seismic network in Russia comprises in total more than 170 seismic stations and 10 datacenters for data acquisition and data processing. The Geophysical Survey of the Russian Academy of Sciences (GS RAS) coordinates the work of all these networks: the continuous monitoring, the current data processing, providing data for research and editing of the seismological catalogues and bulletins.

Teleseismic network

Figure 1. The dataprocessing center building of the Geophysical Survey of the Russian Academy of Sciences in Obninsk.

The teleseismic network of the GS RAS operates around 30 seismic stations and a data center in Obninsk. All stations have broadband recording channels. Approximately half of them (14) have digital equipment; the others use shortperiod and longperiod channels with records on photographic paper. The equipment of 12 digital stations is made available by IRIS and is part of the Global Seismograph Network (GSN). The characteristics of the 12 stations are similar to those of the other GSN stations. The data of the digital stations are transmitted to the data center in Obninsk by telephone in a mode close to real time. Further, the datacenter of the teleseismic network regularly obtains data from other GSN stations and has access to a number of databases outside Russia. The computer network consists of 20 SUN computers and tens of PC's for data processing. The software that is used in the datacenter is developed by the staff of the GS RAS and allows all modern methods of data processing, including data collection in various modes, automatic detection and association of phases, definition of event parameters in an interactive mode and production of the bulletin of seismic events. Figure 1 illustrates the different procedures and data streams within the network and throughput to the archive, other networks and users.

Figure 2. Input and output (products) of the GS RAS Data Center: schematic illustration of the procedures and data streams. GS is the Geophysical survey, CIS is Commonwealth of Independent States and EMERCOM is the Ministry of Emergency of the Russian Federation.

An important component of the teleseismic network is the 24-hour-a-day service to determine the location and magnitude of significant earthquakes in Russia and around the world as rapidly and accurately as possible. Figure 3 shows all the BB stations integrated within the Alert Service of Geophysical Survey RAS.

Figure 3. Map displaying all Broadband stations that contribute to the Alert Service of GS RAS. All stations except PUL are also part of the GSN.

This alert information is communicated to federal and regional government agencies which are responsible for emergency response and to scientific groups. Within less than 30 minutes after an earthquake the "URGENT WARNING" message is send to the Emercom of the Russian Federation, thus providing essential information in emergency situations where urgent measures are required. This includes assistance to stricken areas, life rescue operations and other hazard mitigation measures. Within less than 2 hours an "ALERT MESSAGE" is composed, which contains the origin time of the earthquake, the coordinates of the epicenter, depth of the source, the magnitude and possible destructive impact. For all earthquakes that are felt the intensity distribution is also shown. This "ALERT MESSAGE" is sent to the organizations of the Ministry of Emergency of the Russian Federation, the regional seismological centres of Russia and the countries of the CIS, interested state organizations of Russia and international datacentres. The datacenter of the teleseismic network archives the information of each earthquake in a database, which is accessible through its webpages.

Regional networks

Altay-Sayan region. The Altay-Sayan regional network (networkcode ASRS) monitors the region 46°-56° N and 80°-100° E. The ASRS network consists of 20 stations and two local networks with in total 38 digital stations that operate in the frequency range 0,5-15 Hz and with a 16-24 bit dynamic resolution. The datacenter of the network is situated in Novosibirsk, where the data is processed and the earthquake catalogue is issued. Earthquakes with magnitude larger then 3.0 and felt earthquakes are included in this catalogue which is available on the web together with the digital waveform data of the "Novosibirsk" station.
Baykal region. In the region between 48°-60° N and 96°-122° E the seismic monitoring is carried out by the Baykal regional network (networkcode BYKL). The BYKL network incorporates 24 stations, 13 of which have digital recording equipment, that operates within the frequency range of 0,5-10 Hz and a dynamic resolution of 15-17 bit. The network records annually more than 4000 earthquakes of all sizes. The datacenter of this network is situated in Irkutsk and the seismic events are published in "the Bulletin of earthquakes of Baykal".

Figure 4. The regional network of the Baykal area. For the legend see Figure 5.

Dagestan region. Seismic monitoring of the republic Dagestan in the eastern part of Northern Caucasus is provided by the Dagestan regional network (networkcode DRS). The datacenter of the DRS network is situated in Makhachkala. The network consists of 17 stations equipped with shortperiod seismometers and analog recording.
Kamchatka region. Seismic monitoring of the Kamchatka peninsula and the Komandorkiye Islands is done by the Kamchatka regional network (networkcode KRSC). The KRSC network consists of three local networks and some individual stations. All together 2 digital broadband stations (PET and KAMR), 7 stations with analog recording and 27 shortperiod stations (0,7-20 Hz, 11 bit resolution) with digital recording through a telemetry network. Each local datacenter gathers its own data, manages its own stations and calibrates regularly the seismic instrumentation. The local datacenters are all connected to the regional center in Petropavlovsk, Kamchatka, where all data is collected and archived on laser disks. Effective algorithms enable to store the daily information from all local networks on one disk.
In the regional datacenter the location and magnitude of significant earthquakes are determined on a daily basis and the seismological bulletins are issued. The datacenter of each network provides three levels of access to the data and the results of data processing:
- Digital records of earthquakes and results of provisional processing (bulletins and catalogues) are stored in a database which can easily be accessed through the local computer network (by local users only);
- Bulletins and catalogues are available on a website to the seismological community;
- Rapid warnings on strong earthquakes in Kamchatka are transferred to local administration, in a mode close to real time.

Figure 5. Map of the Kamchatka regional network.

Kola peninsula region. Seismic monitoring of the Kola peninsula, Karelia, the Arkhangelsk area and Spitsbergen is carried out by the Kola regional network (networkcode KORS). The KORS network includes two digital broadband stations (APA and AMDR) and two seismic arrays. The datacenter is situated in Apatity. Each month a catalogue of earthquakes with the results of the processing is send by email to Obninsk.
Sakhalin island region. Seismic monitoring of the Island of Sakhalin, the Kuriles and Primorski Krai is done by the Sakhalin regional network (networkcode SKHL). The SKHL network has 1 broadband digital station (YSS) and 4 digital stations (frequency range 0.02-10Hz and 16 bit dynamic range) on the Island of Sakhalin, 3 analog stations on the Kuriles and 8 analog stations in Primorski Krai. Monitoring of the areas with the strongest earthquakes on the Island of Sakhalin is carried out by Japanese digital instrumentation Datamark and DAT. The datacenter is situated in Yuzhno-Sakhalinsk. Every ten days an event catalogue with the results of the data processing is made and every 5 years the "Seismological bulletin of the Far East" is produced.

Figure 6. Map of the Sakhalin regional network. For the legend see Figure 5.

Northern Caucasus region. The regional network of the Northern Caucasus includes 7 permanent stations, a local network with 5 radio telemetry stations and a seismic array in the area of Kislovodsk. Two stationary stations, the local network and the seismic array have digital recording. Besides the data of the given networks also data from the Dagestan region network (DRS) is used. The datacenter is situated in Obninsk. The results of the data processing are presented in "the Regional catalogue on the region of Northern Caucasus".
Northeast region. In the region of the Magadan area, Chukotka, Okhotsk and the Beringsea seismic monitoring is done by the Northeast regional network (networkcode NERS). The NERS network consists of 11 stations out of which 3 broadband (BILL, MA2 and SEY) and 5 shortperiod stations with digital recording. The datacenter is in Magadan. The data are processed resulting in an event summary and every month a catalogue is issued.

Figure 7. Map of the Northeast regional network. For the legend see Figure 5.

Yakut region. Seismic monitoring of the region of the republic Sakha is provided by the Yakut regional network (networkcode YARS). The YARS network consists of 13 stations. 2 broadband (TIXI and YAK) and 5 short-period stations covering the frequency range 0,02-7 Hz and a dynamic resolution of 16 bit have digital recording. The datacenter is situated in Yakutsk. Results of data processing are presented every 10 days.

Figure 8. Map of the Yakut regional network. For the legend see Figure 5.

click for large figure click for large figure

Figure 9. Comparison of three Afghanistan earthquakes in March 2002 in two different stations. The left picture is station Talaya (TLY) in the Baykal network, distance 27.9 °, the right is station Lovozero (LVZ) in the Kola network, distance 37.3°. The first three traces in both figures show the two deep events (depth is 250 km) on 3 March 2002 with M = 6.0 and M = 6.6. The lower three traces show the shallow event from 25 March 2002 with M = 6.0.

GS RAS cooperates with international and national seismological centers especially for data exchange and integration in the global system of seismic monitoring. The Geophysical Survey of the RAS provides, with its scientific experts in the field of seismic monitoring and instrumentation, the rapid warning services for the central and local authorities and other departments with respect to earthquakes and its possible consequences. The GS RAS collects and archives the data in an extensive seismic database that is available for scientists and researchers:

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