2009 IRISORFEUS Metadata Workshop November 2009 Cairo Egypt

2009 IRIS/ORFEUS Metadata Workshop November 2009 / Cairo, Egypt Establishment of the Libyan National Seismological Network (LNSN): An efforts aimed at assessing and mitigating natural disaster risks on the National and regional scale Abdunnur Ben Suleman, Email: abdunnurs@yahoo. com The Scientific Advisor of the Libyan National Seismological Network (LNSN) & The Chairman of Geophysics Department /Faculty of Science : Al Fateh University

ABSTRACT 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. The recorded number of earthquakes in Libya was not representative of the actual total number before the establishment of the Libyan National Seismograph network. A number of reasons contribute to this fact among which are the small number of seismic stations in the area and the limitations on instrumental sensitivity before 1950. This scientific fact was fully proven after the establishment of the Libyan National Seismograph Network (LNSN) operated since November of the year 2005. The LNSN consists of an up-to-date 15 broadband digital national network stations, utilizing state of the art VSAT communication technology, and a Central Processing Center, located in the City of Ghariyan, Libya.

ABSTRACT This presentation aims to explain in detail the main objectives of the LNSN, both on local and regional scales, and to explain the new picture of the seismicity and seismic hazard of Libya. The newly compiled Libyan catalogue represents the main source of data through which we analytically reanalyze earthquake activity of Libya with the aim of improving the earthquake hazard assessment of the Country. Different sources were used in the compilation process within a geographical window limited by the 19 Deg. N and 35 Deg. N parallels and the 9 Deg. E and 26 Deg. E meridians.

ABSTRACT 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. At first glance the seismic activity map shows dominant trends of seismicity with most seismic activity concentrated along the northern coastal areas. Four major seismic trends were noticeable. A first trend is a NW-SE direction coinciding with the eastern boarder of the Hun Graben. A second trend is also a NW-SE direction in the offshore area and might be a continuation of this trend. The other two trends were located in the western Gulf of Sirt and Cyrenaica platform. The rest of seismicity is diffuse either offshore or in land, with no good correlation with well-mapped faults.

This presentation aims to explain in detail: l l l The Libyan National Seismological Network (LNSN) and its main objectives both on the local and regional scales. Discuss the Recent seismic activity for the period 2005 to 2008 as recorded by the LNSN. Analytically reanalyze earthquake activity of Libya with the aim of improving the earthquake hazard assessment of the Country.

Establishment of the Libyan National Seismological Network (LNSN): An efforts aimed at assessing and mitigating natural disaster risks on the National and regional scale PRESENTATION OULINE l l l Location and Regional Tectonic Setting. Seismicity Before the Establishment of the LNSN. The Libyan National Seismological Network (LNSN) Seismicity After the Establishment of the LNSN. Conclusions.

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.

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 The LNSN consists of an up-to-date 15 broadband digital national network, utilizing state of the art VSAT communication technology, and a Central Processing Center, located in the City of Ghariyan, Libya. Location of the Libyan National Seismological Network (LNSN) Stations.

List of the Libyan Seismograph Network Stations (LNSN) with location and station elevation. Code Lat(deg min) Lon(deg min) Elevation (m) Station. name ALAS LGHD LJBD LJFR LKFR LMSR LSHF LSRT LTBQ LTRP LUJL LUMB LZLA LGHR LMRJ 32 50. 55 11 36. 83 30 01. 00 9 26. 53 30 54. 78 20 11. 89 29 06. 11 15 48. 77 24 09. 68 23 12. 73 32 18. 75 15 00. 50 29 59. 21 14 14. 86 31 04. 87 16 39. 49 32 03. 34 23 55. 26 32 50. 68 13 09. 80 29 07. 15 21 18. 16 26 08. 29 14 45. 12 28 33. 22 17 33. 68 32 07. 32 13 05. 18 32 34. 91 20 52. 54 73 600 49 351 413 114 429 95 139 83 95 474 239 709 408 AL-ASSA GHDAMES ADJABYA JUFRA KUFRA MISRATH SHWAIRF SIRT TOBRUQ TRIPOLI UJELA MURZUK ZALLA GHARYAN AL-MARJ

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 extremely important to formulate a code of practice for designing earthquakeresistant structures especially in the northern part of the country

ﺍﻻﻧﺘﺒﺎﻩ ﺣﺴﻦ ﻋﻠﻰ ﺷﻜﺮﺍ Merci Pour Votre Attention Thank you for Your Attention