1. UGRC 144 Science and Technology in Our Lives/Geohazards
Session 4 – Earthquakes in Ghana
Lecturer: Dr. Patrick Asamoah Sakyi
Department of Earth Science, UG
Contact Information:

2. Session Overview
This session introduces students to earthquake history in Ghana, including past occurrences and locations.
Most people living in Ghana today have never experienced an earthquake, and Ghanaians may find it difficult to associate earthquake disasters with Ghana.
However, evidence based on the history of the Gold Coast/Ghana, modern day seismograph recordings and the geology of Ghana indicates a high earthquake disaster risk for Ghana.
Dr. Patrick A. Sakyi, Dept. of Earth Science

3. Session Outline
The key topics to be covered in the session are as follows:
Topic One – History of Earthquakes in Ghana
Topic Two – Modern Seismographs in Ghana
Topic Three – Earthquake Risk in Ghana
Topic Four - Earthquake Epicenters and the Regional Geological Structures of Ghana
Topic Five – Active Faults in Ghana
Topic Six - Earthquake Risk Map of Ghana
Dr. Patrick A. Sakyi, Dept. of Earth Science

4. Reading List
Unit 1, Section 4 of UGRC 140 II Geohazards – Institute of Continuing and Distance Education
Dr. Patrick A. Sakyi, Dept. of Earth Science

5. History of Earthquakes in Ghana
Topic One
History of Earthquakes in Ghana
Dr. Patrick A. Sakyi, Dept. of Earth Science

6. History of Earthquakes in Ghana
The most significant earthquakes (magnitude 6.0 and above) which caused severe damage are:
Elmina (1615)
Axim (1636)
Accra (1882)
Ho (1906)
Accra (1939).
Dr. Patrick A. Sakyi, Dept. of Earth Science

7. History of Earthquakes in Ghana
The earthquake which was located 40 km offshore to the southwest of Accra shook most of West Africa.
Dr. Patrick A. Sakyi, Dept. of Earth Science

8. History of Earthquakes in Ghana
Minor Historic Earthquakes
Notable minor tremors were also felt in:
Dr. Patrick A. Sakyi, Dept. of Earth Science

9. History of Earthquakes in Ghana
Recent Significant Earthquakes
Since 1939, no earthquake has caused any major destruction in Ghana.
Events that have caused concern since independence have all been centered on Accra.
Dr. Patrick A. Sakyi, Dept. of Earth Science

10. History of Earthquakes in Ghana
Recent Significant Earthquakes
They were of Magnitude 4.5 or less recorded in
Dr. Patrick A. Sakyi, Dept. of Earth Science

11. History of Earthquakes in Ghana
Recent Significant Earthquakes
A recent notable event was a magnitude 4.4 earthquake which occurred on Independence Day
6th March1997.
Dr. Patrick A. Sakyi, Dept. of Earth Science

12. Modern Seismographs in Ghana
Topic Two
Modern Seismographs in Ghana
Dr. Patrick A. Sakyi, Dept. of Earth Science

13. Modern Seismographs in Ghana
Modern day recording of earthquakes begun in Ghana when a 6-component World Wide Standard Seismograph Station (WWSSS) was commissioned in Kukurantumi in the Eastern Region in March 1973.
Later, many more seismographs were installed in south eastern Ghana for the monitoring of earthquakes.
Since 1973 scores of earthquakes, some of magnitude as low as one (1) have been recorded in southern Ghana, and their epicentres determined
Dr. Patrick A. Sakyi, Dept. of Earth Science

14. Earthquake Risk in Ghana
Topic Three
Earthquake Risk in Ghana
Dr. Patrick A. Sakyi, Dept. of Earth Science

15. Earthquake Risk in Ghana
Earthquake hazard means the probability of occurrence of an earthquake of sufficient Magnitude capable of causing damage to the weakest man-made structure.
Risk means the measure of the likelihood of harmful consequences arising from the interaction of a hazard, vulnerable community elements and the environment.
Dr. Patrick A. Sakyi, Dept. of Earth Science

16. Earthquake Epicenters and the Regional Geological Structures of Ghana
Topic Four
Earthquake Epicenters and the Regional Geological Structures of Ghana
Dr. Patrick A. Sakyi, Dept. of Earth Science

17. Earthquake Epicenters and the Regional Geological Structures of Ghana
Dr. Patrick A. Sakyi, Dept. of Earth Science

18. Active Faults in Ghana Topic Five
Dr. Patrick A. Sakyi, Dept. of Earth Science

19. Active Faults in Ghana
All the earthquake activity in Ghana can be associated with three major tectonic zones of weakness active in Ghana.
- Cote d’Ivoire Fault
- Akuapim Fault Zone
- Coastal Boundary Fault
Dr. Patrick A. Sakyi, Dept. of Earth Science

20. Active Faults in Ghana
In the south-west, is the Cote d` Ivoire fault which cuts through Ghana.
Dr. Patrick A. Sakyi, Dept. of Earth Science

21. Active Faults in Ghana
The north-east trending Akuapem fault which intersects with the Coastal Boundary fault just to the west of Accra .
Dr. Patrick A. Sakyi, Dept. of Earth Science

22. Active Faults in Ghana . Near Accra is the Coastal Boundary Fault
Dr. Patrick A. Sakyi, Dept. of Earth Science

23. Active Faults in Ghana . Coastal Boundary Fault
The CBF is a major fault parallel to the coast just a few kilometers off shore and trending east-west.
To the east, this fault most probably strikes inland and continues as the faulted northern margin of the Keta Basin.
Dr. Patrick A. Sakyi, Dept. of Earth Science

24. Active Faults in Ghana . Expected Epicentre
Anywhere along the Akwapim–Togo range (along the Akwapim fault zone)
Out to sea along the entire coast line of Ghana (on the coastal boundary fault)
The intersection of these two faults (near Accra in the area between Weija and Nyanyanu on the coast) would be the most likely location of the next major earthquake in Ghana.
The date and time of such an event cannot be predicted.
Dr. Patrick A. Sakyi, Dept. of Earth Science

25. Earthquake Risk Map of Ghana
Topic Six
Earthquake Risk Map of Ghana
Dr. Patrick A. Sakyi, Dept. of Earth Science

26. Earthquake Risk Map of Ghana
Dr. Patrick A. Sakyi, Dept. of Earth Science

27. END
Dr. Patrick A. Sakyi, Dept. of Earth Science