1. A PAPER PRESENTED AT THE Related Metadata from Seismic Networks”
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
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. 2. THE FRACTURE SYSTEMS IN NIGERIA AND ITS
OUTLINE
GENERAL OVERVIEW OF THE GEOLOGY OF NIGERIA BASEMENT COMPLEX
2. THE FRACTURE SYSTEMS IN NIGERIA AND ITS
RELATIONSHIP TO THE MID-ATLANTIC RIDGE EARTH TREMOR OCCURRENCES IN NIGERIA ACTION TAKEN SO FAR BY THE NIGERIAN GOVERNMENT NTCEP
- NNNSS CGG INSTRUMENTATION/ANALYSIS SOFTWARE
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 GEOLOGICAL FOUNDATION
S/N
STATION NAME
LATITUDE
LONGITUDE
ELEVATION (FT)
GEOLOGICAL FOUNDATION
INSTRUMENTATION 1
Oyo
07°51.660N
03°57.203E
1036
Granite
No instrument installed 2
Ibadan
07°26.015N
03°54.071E
667
Gneiss 3
Ile-Ife
07°32.800N
04°32.815E
902
EP105 broadband seismometer, DR recorder 4
Awka
06°14.561N
07°06.693E
174
Shale and siltstone 5
Nsukka
06°52.011N
07°25.045E
1533
Sandstone 6
Abakiliki
06°23.453N
08°01.474E
268 7
Abuja 8
Toro
10°03.783N
09°04.158E
3187 9
Kaduna
10°26.101N
07°38.484E
2169 10
Minna
09°30.702N
06°26.411E
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. The equipment at each station consists of:
INSTRUMENTATION
The equipment 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
IFE BZ ES
IFE BZ AML
NSU BZ EP
NSU BZ ES
NSU BZ AML
KAD BZ EP
KAD BZ ES
KAD BZ AML
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