1 / 19

C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

THE NIGERIAN NATIONAL NETWORK OF SEISMOLOGICAL STATIONS (NNNSS) BY OLOGUN, C.O., KADIRI, U. A. & YAKUBU, T.A. CENTRE FOR GEODESY AND GEODYNAMICS (CGG), NATIONAL SPACE RESEARCH AND DEVOLOPMENT AGENCY, FEDERAL MINISTRY OF SCIENCE AND TECHNOLOGY, TORO, BAUCHI STATE, NIGERIA A PAPER PRESENTED AT THE

sherry
Download Presentation

C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. THE NIGERIAN NATIONAL NETWORK OF SEISMOLOGICAL STATIONS(NNNSS)BYOLOGUN, C.O., KADIRI, U. A. & YAKUBU, T.A.CENTRE FOR GEODESY AND GEODYNAMICS (CGG),NATIONAL SPACE RESEARCH AND DEVOLOPMENT AGENCY,FEDERAL MINISTRY OF SCIENCE AND TECHNOLOGY,TORO, BAUCHI STATE, NIGERIA A PAPER PRESENTED AT THE IRIS workshop “Managing Waveform Data and Related Metadata from Seismic Networks” Helwan, Cairo, Egypt. 8TH – 17TH NOVEMBER 2009 • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  2. OUTLINE • GENERAL OVERVIEW OF THE GEOLOGY OF NIGERIA BASEMENT COMPLEX • 2. THE FRACTURE SYSTEMS IN NIGERIA AND ITS • RELATIONSHIP TO THE MID-ATLANTIC RIDGE 3. EARTH TREMOR OCCURRENCES IN NIGERIA 4. ACTION TAKEN SO FAR BY THE NIGERIAN GOVERNMENT - NTCEP • - NNNSS - CGG 5. INSTRUMENTATION/ANALYSIS SOFTWARE • 6. THE 9/11 EVENT • 7. CONCLUSION • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  3. GEOLOGY OF THE NIGERIA BASEMENT COMPLEX • Nigeria’s geologic terrain can be broadly divided into two: crystalline basement complex and the sedimentary basins. • The Precambrian basement complex is located within latitudes 7°N and 12°N and longitudes 3°E and 10°E. It forms a large part of the Pan- African mobile belt which lies between the West African Craton to the West and Congo Craton to the Southeast. • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  4. The region has been affected greatly by deformation • and/ or thermal reactivation during the Pan-African • event without extensive sedimentation. • Odeyemi (1981) classified the basement complex • rocks into three major groups, namely: • a suite of rocks comprising of migmatites • and gneiss; • (ii) metasedimentary successions (schist belts) which distinctly exist within the migmatites and gneisses; • (iii) a suite of intrusive syntectonic to late tectonic • granitoids (Older Granites) associated with • pegmatites and aplites. • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  5. Geologic map of Nigeria showing extension of Fracture zones from the Mid-Atlantic ridge to the Nigerian coastline (Whiteman, 1982) • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  6. EARTH TREMORS IN NIGERIA • Nigeria, like other parts of West Africa, lies on the • eastern flank of the Atlantic Ocean and unlike the • Pacific Ocean margins which are characterized by • subduction tectonics and occurrence of • devastating earthquakes, the Atlantic margins are • generally believed to be quiet and free of • diastrophic activities. • However, in recent times, earth tremors have been • reported in some parts of Nigeria. • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  7. Some towns where earth tremors have been reported are: • Lagos and Ile-Ife area in 1933 and 1939 • Warri area in 1933 • Ibadan, Ijebu-Ode, Akure and Shagamu on Saturday, • 28th July and Thursday, 2nd August 1984 • Yola in December, 1984 • Kombani Yaya on 18th June, 1985 • Ibadan on 27th June, 1990 • Okitipupa in 1997 • Akure and Ibadan in 2000 • Ese-odo & Okitipupa on 7th March, 2000 • Minna in April, 2006. • Recently in 11th November, 2009 (Recorded and processed) • Only 4 of these events were instrumentally recorded • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  8. ACTION TAKEN SO FAR BY THE NIGERIAN GOVERNMENT • SETTING UP OF THE NTCEP • ESTABLISHMENT OF NNNSS • ESTABLISHMENT OF CGG • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  9. LOCATION OF NIGERIAN SEISMOLOGICAL STATIONS • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  10. Map of Nigeria showing location of seismographic Station (■-- Functional Stations) • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  11. A Typical CGG Station • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  12. INSTRUMENTATION • Theequipment at each station consists of: • DR-4000 data acquisition system • EP-105 broadband seismometer or SP-400 • short period seismometer • Global Positioning System (GPS) • Power source (Solar electricity and battery) • These are products of Eentec Scientific Inc., • U.S.A. • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  13. DR-4000 Recorder EP-105 Sensor • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  14. DATA ANALYSIS SOFTWARE • The SEISAN Seismic analysis software is a complete set of programs for • analyzing earthquakes from analog and digital data. • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  15. PRELIMINARY RESULT OF 11TH SEPTEMBER 2009 EARTHQUAKE DATE OF OCCURRENCE: 11 SEPTEMBER, 2009 ORIGIN TIME: 04:10:18.6 FOCAL DEPTH: FIXED TO 10 KM LOCAL MAGNITUDE: 4.8 MOMENT MAGNITUDE: 4.0 EPICENTRAL DISTANCE: 129 KM WEST OF LAGOS RMS: 0.4 • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  16. LOCATION PARAMETERS STAT SP IPHASW HRMM SE AMPLIT PERI AIN TRES DIS IFE BZ EP 310 58.96 51 0.6910 276 IFE BZ ES 311 26.89 51 -0.3110 276 IFE BZ AML 311 32.04 17078.2 0.26 276 NSU BZ EP 311 34.81 51 -0.6310 573 NSU BZ ES 312 31.82 51 0.3210 573 NSU BZ AML 313 27.30 2450.3 0.49 573 KAD BZ EP 311 55.14 51 -0.0510 731 KAD BZ ES 313 5.64 51 -0.0310 731 KAD BZ AML 313 45.44 1501.8 0.35 731 KEY STAT: Station AMPLIT: Amplitude SP: Instrument type, Component PERI: Period IPHASW: Phase ID AIN: Angle of incidence HR: Hour TRES: Travel time residual MM: Minute DIS: Epicentral distance SE: Second • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  17. C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  18. CONCLUSION • Nigeria is not located within the major • seismic belt of the world • Minor earthquakes and/or earth tremors had • occurred in different parts of the country. • Presently, 4 stations are functional. • Efforts are being made to install equipment • in 7 additional stations and network all the • stations for effective data acquisition and • proper monitoring of seismic activities in the • country. • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

  19. THANK YOU • C CENTRE FOR GEODESY AND GEODYNAMICS, NASRDA , TORO, BAUCHI STATE

More Related