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Broadband Earthquake Monitoring at OAUIFE Station, Nigeria

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Title: Broadband Earthquake Monitoring at OAUIFE Station, Nigeria


1
Broadband Earthquake Monitoring at OAUIFE
Station, Nigeria
  • Dr Adepelumi, A. A
  • Department of Geology,
  • Obafemi Awolowo University,
  • Ile-Ife, Osun State
  • Email adepelumi_at_gmail.com or aadepelu_at_oauife.edu.
    ng
  • Phone 234-08067163658

1st January, 2009
2
Seismology
  • In November 2007, Guralp system was installed at
    OAUIFE seismic station (7º 31'23"N and 4º31'27"E)
    through the funding provided by UNESCO office in
    Italy.
  • Inverter and Solar Panel were installed in
    November 2008 for the smooth running of the
    seismic station.

3
(No Transcript)
4
Some of the Events Recorded at OAUIFE Earthquake
station
5
Iceland May 29, 2008
6
Mexico Event- 2008
7
Tonga Event- 2008
8
OAUIFE Observatory
9
Earthquake Facilities at OAUIFE
10
Properties of the Seismometer
11
Iceland Earthquake
  • "Iceland is sitting on a plate boundary where the
    North America and Eurasian plates are drifting
    apart. So earthquakes are common but large
    earthquakes are relatively rare,"
  • On 29th May, 2008, A strong earthquake measuring
    6.1 hit southern Iceland, 50km from the capital,
    Reykjavik.
  • The US Geological Survey said the earthquake
    struck at 1546 GMT at a shallow 6.2 miles (10
    km). The earthquake was also picked at the same
    time at OAUIFE

12
Implication of the Iceland Teleseismic to Nigeria
  • Insights into the structure of the upper mantle
    beneath Southwestern Nigeria.
  • Lithospheric structure of Southwestern Nigeria
    from the teleseismic data.
  • Insights into the Crustal structure beneath
    Southwestern Nigeria.
  • Character and kinematics of the Megashear systmem
    in the Gulf of Guinea Implications for tectonic
    evolution of Southwestern Nigeria.

13
Iceland Earthquake (OAUIFE)
14
Iceland Earthquake - Sandpoint, USA
15
Nigeria as a case study
16
Recent Seismicity in Nigeria
  • Although, no active faults have been established
    in Nigeria, however, a careful review of
    seismicity record in Nigeria had showed that
    Nigeria may not be aseismic as has hitherto been
    believed.
  • Recent events in Nigeria Ijebu-Ode (July and
    August, 1984) Gulf of Guinea (December, 1984).
    Warri (1933), Lagos (1939) Umuahia (July, 1961)
    Kundunnu, Bauchi (1981) Dambatta, Kano (July,
    1975) Yola ( December, 1984) and Gombe (June,
    1985).
  • Thus monitoring and prediction of earthquake
    hazards could begin by a proper documentation of
    the pathways through which they emanate, using
    seismological data.

17
Long Term Earthquake Prediction Southwestern
Nigeria
  • The Empirical Earthquake Recurrence Model a
    time-dependent model, was employed to predict the
    probabilistic occurrences of earthquakes in the
    Ijebu-Ode and environs between the year 2008 and
    2028.
  • This probability model takes the mean recurrence
    intervals and standard deviation of historic
    earthquake events in this area in order to
    determine the probability of earthquakes
    occurrence for the predicted years.

18
Probability of Recurrence of Earthquake of
Intensity V-VII in Southwestern Nigeria
19
Probability of Recurrence of Earthquake of
Intensity V-VII in Southwestern Nigeria
  • The results of the model showed that the
    probability of earthquake occurrence in the study
    area between the year 2008 and 2028 increased
    from 2.8 to 91.1.
  • The result also showed that the probability of 2
    events occurring has the highest likelihood
    within the predicted years.

20
Conclusion
  • Therefore, it is instructive as a necessary
    measure to henceforth incorporate seismic
    criteria in the site investigations for design
    and construction of major and sensitive
    structures like Nuclear power plants the country
    is seriously considering as alternative source of
    energy for electricity generation, whose sudden
    damage can lead to disruption of major essential
    services, loss of lives and property and general
    degradation of the environment.
  • Long Term Earthquake Monitoring should be
    embraced by Nigeria.

21
Future Plans
  • Expand OAUIFE network to a comprehensive and
    effective earthquake Information System Center
  • Acquire through UNESCO more sensitive
    seismometers that will serve as a Early
    Earthquake Warning System
  • Study the Crustal and Mantle structure beneath
    Southwestern Nigeria.

22
Acknowledgments
  • UNESCO and TWAS for the financial support.
  • Dr. Eck van, Torild for support.
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