Well, here is a massive oversimplification of plate tectonics. The African plate is much larger than the African continent, so the plate movements that lead to earthquakes and volcanoes generally occur underwater. That said, the East African rift is well known for its volcanoes. Generally speaking, however, we only note volcanic eruptions when they are particularly devastating or unexpected. Most are neither.
Tsunamis are also seismic events, caused by earthquakes under the ocean floor. They occur most frequently in the Pacific because it is the most active area, seismically. That's why Japan has many of them. Africa does get them, too, but it is a rarer event.
As for hurricanes, their formation requires warm, open stretches of water. They thus generally form off the Atlantic coast of Africa and always travel west. Sometimes they do affect the Cape Verde islands, but usually before they become very strong. Cyclones form in the Pacific, but generally speaking, there are more land masses between the area where they form and Africa. However, they do hit Africa - just not as frequently.
We just don't hear about Africa much at all, as the PP pointed out.
Wow. You don't often see such a well-supported answer, confined to the question, on DCUM.
