410 likes | 572 Views
Establishment of the L ibyan N ational S eismological N etwork: An effort aimed at assessing and mitigating natural disaster risks on the National and regional scale. Abdunnur Ben Suleman. Also @ Geophysics Department, Al-Fateh University / Tripoli.
E N D
Establishment of the Libyan National Seismological Network: An effort aimed at assessing and mitigating natural disaster risks on the National and regional scale Abdunnur Ben Suleman Also @ Geophysics Department, Al-Fateh University / Tripoli Libyan National Seismological Network @ Managing Waveform Data and Related Metadata For Seismic Networks Cairo-Egypt, 8-17 November,2009
Al Marj Earthquake:19 February 1963 This presentation aims to explain: • Seismic Activity Before the establishment of the LNSN • Overview of the Libyan National Seismological Network (LNSN) • Seismic activity using additional data as recorded by the LNSN. • Conclusions and Future Planes
Location and Regional Tectonic Setting The tectonic evolution of Libya, located at the northern extreme of the African continent, has yielded a complex crustal structure that is composed of a series of basins and uplifts. The present day deformation of Libya is the result of the Eurasia-Africa continental collision.
Mesozoic rift basins of NE and Central Africa (after Bosworth, 1994). The Sirt and northern Egypt rifts lie within remobilized Neoproterozoic continental terranes along the edges of the East Saharan and Nile Cratons and the Sudan Shield (Vail, 1991).
Table 1 : Inventory of available studies on earthquake effects in Libya up to 1900 Table 2 : Earthquakes affecting Libya between 1903 and 1935 (M≥5.0)
Earthquake Observations in Libya • Late 70’s with one Station Located at The Al Fateh University in Tripoli • In Early 90’s with Two stations located in Gharian and AlMaraj (In a joint project with ETHZ) • November 2005: The Libyan National Seismological Network (LNSN)
Seismicity Before the Establishment of the LNSN Al Maraj Earthquake: 21 February 1963 (5.3); 300 killed and 12,000 homeless Tripoli Earthquake: 1974 (Ms5.6) Al Qaddahia Earthquake Sequence: 19 April 1935 (mb=7.1) 20 April 1935 (mb=6.0 &mb=6.5) 1939 (5.6)
The LNSN network was designed to monitor local, regional and teleseismic activities, as well as to provide high quality data for research projects both locally and on the regional and global scale Tripoli The LNSN consists of 15 stations (3 very broadband, and 12 broadband), utilizing state of the art VSAT communication technology, and a Central Processing Center, located in the City of Ghariyan In Addition to 20 portable stations
The continuous data is forwarded in a near real-time to a central data acquisition and processing facility, via VSAT communication system, where it is automatically processed. • All stations are solar powered and are equipped with a 24-bit digitizer and VSAT communication system. • Each site acquires continuous data and relays this data directly to the central processing facility via satellite. • All data received at the central hub is forwarded to two-server acquisition system via a single LAN connection. • Each server records the continuous data set to disk based ring buffer and distributes the data in near real-time for automatic processing of seismic events.
List of the Libyan Seismograph Network Stations (LNSN) with location and station elevation. CodeLat(deg min)Lon(deg min)Elevation (m)Station. name LASA 32 50.55 11 36.83 73 AL-ASSA LGHD 30 01.00 9 26.53 600 GHDAMES LJBD 30 54.78 20 11.89 49 ADJABYA LJFR 29 06.11 15 48.77 351 JUFRA LKFR 24 09.68 23 12.73 413 KUFRA LMSR 32 18.75 15 00.50 114 MISRATH LSHF 29 59.21 14 14.86 429 SHWAIRF LSRT 31 04.87 16 39.49 95 SIRT LTBQ 32 03.34 23 55.26 139 TOBRUQ LTRP 32 50.68 13 09.80 83 TRIPOLI LUJL 29 07.15 21 18.16 95 UJELA LUMB 26 08.29 14 45.12 474 MURZUK LZLA 28 33.22 17 33.68 239 ZALLA LGHR 32 07.32 13 05.18 709 GHARYAN LMRJ 32 34.91 20 52.54 408 AL-MARJ
NASG North African Seismological Group
Conclusions Detailed investigations of the Libyan seismicity indicates that Libya has experienced earthquakes of varying magnitudes and that there is definitely a certain amount of seismic risk involved in engineering projects, particularly in the northern regions.
Conclusions The Seismicity map of Libya, using the new data as recorded by the LNSN gives a better picture of the seismicity of Libya and suggested that the country is indeed a seismic prone country with a clear seismic cluster areas in the northern part of the country.
Conclusions It is extremelyimportant to formulate a code of practice fordesigning earthquake-resistant structures especially in the northern part of the country
شكرا على حسن الانتباه Merci Pour Votre Attention Thank you for Your Attention